T E C H N I C A L REPORT STANDARD T I T L E P A G F
1. Report N o .
2. Government A c c e s s i o n No.
3.
---.
R e c r p ~ e n t ' sCorolog N o .
i
FHWAITX-82/6+210-3
--
4 . T l t l e and S u b t ~ t l e
An A p p l i c a t i o n o f RF Data Transmission
i n Freeway Ramp Metering
I
-- .-
- -.
September 1981
6. P e r f o r m ~ n gOrgonlzotlon Code-.
1
Gene P. R i t c h
9 . P e r f o r m i n g O r g a n i z o t l o n N a m e and Address
-
Research Report 210-9
10. Work U n l t N o .
Texas T r a n s p o r t a t i o n I n s t i t u t e
The Texas A&M U n i v e r s i t y System
College S t a t i o n , Texas 77843
11. C o n t r a c t or Grant NO.
Study 2-18-77-210
l 3 . T y p e o f Report and P e r i o d Covered
September 1976
Interim
-September 1981
1 2 . Sponsoring Agency Name and Address
Texas S t a t e Department o f Highways and P u b l i c
T r a n s p o r t a t i o n , T r a n s p o r t a t i o n P l a n n i n ~D i v i s i o n
P. 0. BOX 5051; A u s ~ - i n ,Texas 78763
1
14. Sponsoring Agency c o d a
15. Supplementary N o t e s
Work done i n cooperation w i t h DOT, FHWA.
Study T i t l e : E v a l u a t i o n o f Urban Freeway M o d i f i c a t i o n s
A r a d i o frequency (RF) t r a n s c e i v i n g system was employed as t h e
i n t e r c o n n e c t between entrance ramp c o n t r o l l e r s on 1-30 i n F o r t Worth,
Texas. A f t e r t h e RF system was i n s t a l l e d , a s h o r t and i n t e n s i v e study
was conducted t o determine i f equipment f a i l u r e o r i n t e r f e r e n c e was
occurring. A f t e r s i m u l a t i n g more than 6 months o f e q u i v a l e n t ramp
c o n t r o l o p e r a t i o n , no e r r o r s were detected.
17. K e y Words
18. Di t r i b u t i o r j Statsment
Freeway ramp metering, r a d i o frequency
t r a n s c e i v i n g system, i n t e r c o n n e c t i n g .
m.
1 9 . Security C l o s s l f . ( o f this report)
Unclassified
Form
DOT F 1700.7
(6-69)
No R e s t r i c t i o n . T h i s document i s a v a i l a b l e t o t h e pub1 i c through t h e National
Technical Information Service, 5285 P o r t
Royal Road, S p r i n g f i e l d , V i r g i n i a 22161.
I
S e c u r i t y C l o s r i f . ( o f t h i s page)
Unclassified
I
L_________
.
21. No. of P o g e s
I
22. Prnce
82
1
I
1
AN APPLICATION OF RF DATA TRANSMISSION
I N FREEWAY RAMP METERING
Gene P. R i t c h
A s s o c i a t e Research S p e c i a l i s t
Research Report 210-9
Eva1 u a t i o n o f Urban Freeway
Modifications
Research Study Number 2-18-77-210
Sponsored b y t h e Texas
S t a t e Department o f Highways and P u b l i c T r a n s p o r t a t i o n
I n Cooperation w i t h t h e
U.S. Department o f T r a n s p o r t a t i o n
Federal Highway A d m i n i s t r a t i o n
Texas T r a n s p o r t a t i o n I n s t i t u t e
Texas A&M U n i v e r s i t y
C o l l e g e S t a t i o n , Texas
September 1981
ACKNOWLEGEMENT
The author wishes t o thank M r . Robert Jenkins and M r . Ed D a i l y and
t h e i r s t a f f from D i s t r i c t 2 i n F o r t Worth f o r t h e i r cooperat?on i n
developing, i n s t a l l i n g and o p e r a t i n g t h e RF system.
Thanks go t o M r . Michael
J. Faul kner o f T.T. I . f o r h i s l e a d e r s h i p i n s e t t i n g up and executing t h e
f i e l d s t u d i e s and t o Nada Huddleston, Janet Bowman and Richard B e r r y f o r
t h e i r assistance i n t h e c o l l e c t i o n o f t h e f i e l d data.
Abstract
ASSTRACT
A radio frequency ( R F ) transceiving system was employed as the
interconnect between entrance ramp controllers on 1-30 in Fort Worth,
Texas.
After the RF system was installed, a short and intensive study
was conducted t o dete,rniine i f equipment f a i l u r e or interference was occurring.
.After simulating more t h a n 6 months of equivalent ramp control operation,
no errors were detected.
DISCLAIMER
The c o n t e n t s o f t h i s r e p o r t r e f l e c t t h e views o f t h e a u t h o r who i s
r e s p o n s i b l e f o r t h e f a c t s and t h e accuracy o f t h e data presented h e r e i n .
The c o n t e n t s do n o t r e f l e c t t h e o f f i c i a l views o r p o l i c i e s o f t h e
Federal Highway A d m i n i s t r a t i o n .
T h i s r e p o r t does n o t c o n s t i t u t e a
standard, s p e c i f i c a t i o n o r r e g u l a t i o n .
Sumnary
SUMMARY
To o p e r a t e t h e e n t r a n c e ramp c o n t r o l l e r s on a freeway system based
on o t h e r t h a n l o c a l c o n d i t i o n s r e q u i r e s an i n t e r c o n n e c t i n g system.
The
i n t e r f a c i n g c i r c u i t s , c o n t r o l p o i n t s and l o g i c a r e a v a i l a b l e i n t h e p r e s e n t
ramp c o n t r o l equipment t o p r o v i d e system c o n t r o l
.
U t i l i z a t i o n o f the
system c o n t r o l concept r e q u i r e s a master l o c a t i o n ( n o r m a l l y l o c a t e d a t a
b o t t l e n e c k t o freeway f l o w ) and s l a v e u n i t s ( f u r t h e r upstream e n t r y p o i n t s ) .
When flow c o n d i t i o n s on t h e freeway worsen a t t h e master l o c a t i o n , a command
w i l l be i s s u e d v i a t h e i n t e r c o n n e c t i n g system t o t h e s l a v e l o c a t i o n s .
The
m e t e r i n g of e n t e r i n g ramp t r a f f i c a t t h e s l a v e l o c a t i o n w i l l r e f l e c t t h e
master command t o m o d i f y t h e e n t r y r a t e a t t h e upstream p o i n t s unless l o c a l
c o n d i t i o n s o v e r r i d e t h e command.
The use o f RF equipment as t h e i n t e r c o n n e c t i n g
system o f f e r s a v i a b l e a1 t e r n a t i v e t o t h e irnplenientation o f a d i r e c t w i r e 1 i n e
interconnect.
RF equipment b e i n g manufactured and u t i l i z e d as s t a t u s m o n i t o r i n g
and r e p o r t i n g systems was i n v e s t i g a t e d .
The RF equipment was s p e c i f i e d , purchased and i n s t a l l e d by f o r c e s o f t h e
S t a t e Department o f Highways and P u b l i c T r a n s p o r t a t i o n ' s (SDHPT) D i s t r i c t 2 o f f i c e on
1-30 i n F o r t Worth.
One monitoring/RF t r a n s m i t , t h r e e RF r e c e i v e r / a n n u n i c a t o r
and one RF r e c e i v e r / t h e r m o g r a p h i c p r i n t e r u n i t s were i n c l u d e d .
Each u n i t ,
w i t h t h e e x c e p t i o n o f t h e p r i n t e r which was i n s t a l l e d a t t h e D i s t r i c t ' s
S i g n a l Shop, was housed i n an e n c l o s u r e t h a t was r e a d i l y accommodated i n s i d e
a l a r g e r c o n t r o l l e r c a b i n e t , which a l s o c o n t a i n e d t h e r e g u l a r components o f
a ramp m e t e r i n g u n i t which i n c l u d e d t h e c o n t r o l l e r , l o o p d e t e c t o r s , e t c .
The
t r a n s m i t t e r (master) s i t e r e q u i r e d a 2 0 - f o o t wooden p o l e f o r antenna e l e v a t i o n
w h i l e t h e r e c e i v e r antennae were a t t a c h e d t o t h e t o p of 1 0 - f o o t v e r t i c a l
s e c t i o n s o f two-inch s t e e l p i p e .
The i n t e r c o n n e c t i n g o f t h e o u t p u t c o n t r o l
p o i n t s from t h e ramp c o n t r o l l e r t o t h e i n p u t s i d e o f t h e m o n i t o r c i r c u i t s
completed t h e i n s t a l l a t i o n a t t r a n s m i t t e r s i t e .
S i m i l a r attachments were
made between t h e o u t p u t s o f t h e annunicators and t h e i n p u t s t o t h e ramp
controllers a t the receiver sites.
'The RF equi pment was p l aced under a 1 icense a1 ready issued t o t h e
SDHPT.
An unmanned t r a n s m i t t e r must adhere t o t h e f o l l o w i n g general Federal
Communications Commission (FCC) guide1 i n e s :
1 ) S t a t i o n address must be given,
2 ) Message d u r a t i o n must n o t exceed 2 seconds,
3 ) Continous t r a n s m i s s i o n must be i n h i b i t e d ,
4 ) A minimum o f s i x t y seconds o f s i l e n c e must separate transmissions, and
5 ) The message can n o t be repeated more than t h r e e times.
A s h o r t and i n t e n s i v e study was designed whereby as many RF messages
( t r a n s m i s s i o n s ) were t o be made as p o s s i b l e .
each message, b u t t h r e e transmissions
S t a t i o n addresses remained i n
were s e n t i n 16 seconds.
A test
program was loaded i n t o an unused p o r t i o n o f t h e ramp c o n t r o l l e r memory which
enable t h e observer t o program each t e s t message and data s e t .
The ramp
c o n t r o l l e r issued s e l e c t i v e messages t o t h e m o n i t o r i n g t r a n s m i t t e r u n i t a t
c o r r e c t i n t e r v a l s o f time.
Observers were s t a t i o n e d a t each s l a v e c o n t r o l l e r
t o v e r i f y t h e accuracy o f t h e r e c e i v e d message.
as e r r o r s .
D i f f e r e n c e s were recorded
The p r i n t e r monitored and documented each t r a n s m i t t e d message.
The RF t e s t was conducted over a three-day p e r i o d a t t h r e e t i m e p e r i o d s o f
t h e day; 6:30-8:30 AM, 1 1 : O O AM t o 1:00 PM, and 3:30-6:00
PM.
Throughout t h e t e s t p e r i o d , t h e p r i n t e r was e x p e r i e n c i n g s p u r t s o f
" f a l s e " messages.
Comparisons o f t h e "good" p r i n t e r d a t a w i t h t h e t r a n s m i t t e d
data i n d i c a t e d a l l messages were accurate; i . e . a l l b i t s t r a n s m i t t e d were
r e c e i v e d i n t h e c o r r e c t manner.
The d a t a c o l l e c t e d a t t h e s l a v e ( r e c e i v e r )
l o c a t i o n s when compared w i t h t h e t r a n s m i t t e d d a t a i n d i c a t e d small e r r o r s were
present a t the receiver s i t e s .
Since t h e p r i n t e r experienced no e r r o r s , e r r o r s
a t field observed locations were attributable t o human error.
The RF t e s t
was successful in t h a t the quantity of messages transmitted during the
test represented 6 months of normal system control ramp metering operation
without an error.
Exact costs can be given for the equipment used in the RF installation.
The equipment compares favorably with an a1 ternate direct burial wi re1 ine
interconnect.
TABLE OF CONTENTS
Page
............................
STUDY OBJECTIVES . . . . . . . . . . . . . . . . . . . . . . . . . .
STUDYSITEDESCRIPTION. . . . . . . . . . . . . . . . . . . . . . .
EQUIPMENT DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . .
TEST THEORY . . . . . . . . . . . . . . . . . . . . . . . . . . . .
THETESTSEQUENCE . . . . . . . . . . . . . . . . . . . . . . . . .
THE TEST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TESTRESULTS . . . . . . . . . . . . . . . . . . . . . . . . . . . .
COST COMPARISCIN . . . . . . . . . . . . . . . . . . . . . . . . . .
CONCLUSIONS AND RECOMMENDATIONS . . . . . . . . . . . . . . . . . .
REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
APPENDICES . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
INTRODUCTION
SUMMARY
..............................
1
3
9
15
20
25
34
40
47
50
53
54
iv
LIST OF FIGURES
Page
Figure
1
Study S i t e 1-30 F o r t Worth .
. . . . . . . . . . . . . . . .
11
2
RF Equipment L o c a t i o n s .
. . . . . . . . . . . . . . . . . .
Summit Entrance Ramp . . . . . . . . . . . . . . . . . . . .
Montgromery Entrance Ramp . . . . . . . . . . . . . . . . .
12
28
10
. . . . . . . . . . . .
CPU Panel Module Assignments a t T r a n s m i t t e r S i t e . . . .
New Data Set Being Pinned . . . . . . . . . . . . . . .
D i s p l a y Panel Module D e f i n i t i o n s a t Receiver S i t e s . . .
New Data Set - I n i t i a l Transmission . . . . . . . . .
T y p i c a l Slave l l n i t Observation During RF T e s t . . . . .
11
Comparison o f Messages a t P r i n t e r S i t e .
3
4
5
6
7
8
9
F r o n t a l Face o f Ramp C o n t r o l l e r
.
.
.
.
.
.
13
13
.
.
.
.
.
.
39
. . . . . . . . . .
45
30
31
32
33
LIST OF TABLES
Page
General S p e c i f i c a t i o n s o f RF Equipment .
19
Typical
29
RF Test
. . . . . . . . .
Test Data Set . . . . . . . . . . . . . . . . . .
Results . . . . . . . . . . . . . . . . . . . . .
44
RF I n t e r c o n n e c t F a i 1ures and S y s t e r n 4 ~ o n t r o lE f f e c t
on RampMetering . . . . . . . . . . . . . . . . .
46
System Costs and
49
. . . .
Estimates . . . . . . . . . . . . . . . .
Approximate Conversions to Motric Measures
Symbol
When Y o u K n o w
Multiply b y
T o F~nd
METRIC CONVERSION FACTORS
-iD
- m
- - - N
.- -
Symbol
L=
Svmbol
Approximate Conversions from Metric Measures
When Y o u Know
Multiply b y
T o Find
Symbol
.-
N
-- - 0
- -N
- - =
.
S
-- U
--- -2
- - - 5
- ---- " --- - ---- - f
--- n
.UI
--- =
N
--- .- - - =
n
-- =
-- ---0,
--- =
7
-- a0
W
--- -- =
- h
--- =
- - w
- LJ
--m .-- - 0
---- -m
-- =
- -w
- -0)
LENGTH
-
-- =
-- -3
-- =
- =
LENGTH
7
in
inches
feet
yards
miles
It
vd
mi
'2.5
30
0.9
1.6
centimeters
centimetws
matars
kilometers
cm
cm
m
km
squarecentimeters
square meters
square meters
square k i l o n ~ e t e r s
hemares
cm'
ma
m'
km'
ha
AREA
in'
ft'
vd
square
square
quare
square
awes
'
mt'
inches
feat
yards
miln
6.5
0.09
0.8
2.6
0.4
MASS (weight)
oz
Ib
28
0.45
0.9
ounces
pounds
short t o n s
grams
k~lograrns
tonnes
I
kg
t
(2000I b l
VOLUME
f1 02
teaspoons
tablespoons
f l u i d ouncos
C
Cupr
PI
qt
011
ft'
vd'
pints
quarrr
gallons
c u b l c feet
c u b i c yards
tSP
T~SP
5
15
30
0.24
0.47
0.05
3.8
0.03
0.76
milliliters
milliliters
milliliters
litorr
liters
liters
liters
c u b i c meters
c u b i c meters
TEMPERATURE (exect)
Fahrenheit
tamperature
OF
' 1 In
-
519 (after
subtracting
ml
ml
ml
I
I
I
I
m'
m
'
- -.(0
_
0.04
0.4
3.3
1.1
0.6
millimetsrs
centimeters
met MS
metws
kilometers
- . -.-
-
_
-
2
7
-
Celsius
temperature
P
--
=-=
-U
-
inches
inches
feet
yards
miles
AREA
-
-
2.54 ( e x a c t l y ) . F o r other exacl conversions a n d m o r e d g t a i l d tables, m e N B S
286. U n ~ t os f W e ~ g h ~and
s Meacurei, Prica $2.25.SO C l t a l o g N o . C13.10:286.
MIS. Publ.
mm
cm
m
m
k m
cm'
m
km'
square centirnerers
square m a e r r
square kilometers
ha
hectrr~110.000m'l
'
0.1 6
1.2
0.4
2.5
square inches
square yards
square mlles
acres
MASS (weight)
0
ko
1
grams
kilograms
t o n n n (1000kg1
0.035
2.2
1.1
ourues
p o u n ds
short r o n r
VOLUME
ml
I
I
I
rn'
"la
0.03
2.1
1.06
0.26
35
1.3
milliliters
liters
liters
liters
cubic meters
c u b i c meters
f l u i d ounces
pints
quarts
wltoni
cubic feet
cubic yards
TEMPERATURE (exact)
0
C
Celsius
temperature
915 ( t h e n
32)
add
Fahrenhe~t
temperature
tn'
vd'
miy
Section 1
Introduction
INTRODUCTION
The d i r e c t w i r e l i n e i n t e r c o n n e c t i o n o f i n t e r s e c t i o n a l c o n t r o l s i g n a l s
on s t r e e t systems f o r c o n t r o l purposed has been i n use f o r a l o n g time.
Past
and present entrance ramp metering systems have used d i f f e r e n t techniques of
d i r e c t w i r e l i n e i n t e r c o n n e c t i o n t o p r o v i d e f o r system-wide c o n t r o l d e c i s i o n
making.
An entrance ramp c o n t r o l i n s t a l l a t i o n on 1-30 i n F o r t Worth, Texas has
ramp c o n t r o l l e r s f o r which an i n t e r c o n n e c t i s warranted.
As an a l t e r n a t e
t o a w i r e l i n e i n t e r c o n n e c t i n g system, a data t r a n s m i s s i o n system u t i l i z i n g
r a d i o frequency (RF) equipment was s p e c i f i e d , purchased and i n s t a l 1ed by
D i s t r i c t 2 o f t h e S t a t e Department o f Highways and P u b l i c Transpc, c a t i o n
(SDHPT).
While t h e RF equipment has been i n use i n t h e o i l and gas p r o d u c t i o n
i n d u s t r y f o r some years, t h e entrance ramp i n t e r c o n n e c t r e p r e s e n t s t h e f i r s t
a p p l i c a t i o n f o r t h e SDHPT.
Section 2
Study O b j e c t i v e s
STUDY WORK TASK OBJECTIVES
1)
Determine t h e d a t a t r a n s m i s s i o n needs and requirements f o r t h e s e l e c t e d
s u r v e i l l a n c e and c o n t r o l equipment used i n freeway o p e r a t i o n .
The s e l e c t e d s t u d y s i t e i s d e s c r i b e d i n d e t a i l i n S e c t i o n 3.
The s t u d y
p l a n emphasizes t h e use o f t h e system c o n t r o l programmed l o g i c as c o n t a i n e d
i n t h e TransTronics rarup c o n t r o l l e r s (See Appendix A).
Three p o i n t s o f i n p u t
t o t h e c o n t r o l 1 e r enables i t t o become r e m o t e l y corr~puterc o n t r o l l e d .
p o i n t s p r o v i d e up t o f i v e segmenter l e v e l s t o be recognized.
The 3
Therefore,
t h e RF equipment must be capable o f p r o v i d i n g a t l e a s t 3 p o i n t s i n a p a r a l l e l
manner.
Since t h e freeway averaging t i m e ranges from 0.5 m i n u t e
'3
7 . 5 minutes,
t h e RF equipment should be capable o f sensing, sending, r e c e i v i n g , and p r e s e n t i n g
i n f o r m a t i o n w i t h i n t h e 0.5 minute as a minimum turnaround t i m e .
Particular
emphasis was placed on i n s u r i n g t h a t t h e proposed RF equipment presented
t h e 3 p o i n t s i n a p a r a l l e l manner w i t h i n m i l l i s e c o n d s o f each o t h e r .
This i s
i n c o n t r a s t t o a s e r i a l f a s h i o n p o i n t - t o - p o i n t p r e s e n t a t i o n where problems c o u l d
be caused w i t h i n t h e r e c e i v i n g ramp c o n t r o l l e r as t o which c o n t r o l l e v e l i s
being t r a n s m i t t e d .
Another r e q u i r e m e n t t o be considered i n t h e s e l e c t i o n of t h e RF equipment
i s t h e s t a t e change c o n d i t i o n .
Under remote computer c o n t r o l , t h e s t a t e s o f
t h e 3 i n p u t p o i n t s a t t h e s l a v e c o n t r o l l e r must remain unchanged u n t i l t h e n e x t
n o t i f i c a t i o n from t h e remote computer i s r e c e i v e d .
Therefore, t h e RF e q u i p -
ment should o n l y f u n c t i o n when a change i s noted a t t h e master l o c a t i o n .
The equipment a t t h e s l a v e l o c a t i o n should c o n s t a n t l y p r e s e n t t h e l a s t r e c e i v e d
state o f the 3 points.
It i s unnecessary f o r any RF t r a n s m i s s i o n t o occur
except a t t h e change o f master l o c a t i o n .
2)
Survey e x i s t i n g manufacturers equipment and determine c o s t s .
The d a t a communications equipment n o r m a l l y l i n k e d w i t h RF t r a n s m i s s i o n
equipment i s designed t o c a r r y much l a r g e r and more complex telecommunicat i o n s systems than r e q u i r e d f o r t h i s a p p l i c a t i o n .
A l l such equipment f a r
exceeds t h e requirements f o r s i g n a l c o n t r o l a p p l i c a t i o n and i s n o t c o s t
effective.
T h e r e f o r e manufacturers of f i r e and s e c u r i t y alarms systems
were questioned as t o t h e o p e r a t i o n s o f t h e i r equipment.
As a general
r u l e , these types o f RF communication systems c o n t a i n few i n p u t s and
o u t p u t s , p r o v i d e s i m p l i s t i c communications schemes and r e t a i n a m a i n t a i n a b i l i t y t h a t can be p r o v i d e d by s k i 1 l e d personnel.
Two n a t i o n a l l y known companies produce a l i n e o f a l a r m systems
designed t o o p e r a t e w i t h RF t r a n s m i s s i o n from remote l o c a t i o n s .
The
c o n t r o l l e r a t t h e t r a n s m i t t e r s i t e c o n t i n u a l l y samples sensor s t a t u s .
A
sensor a c t u a t i o n causes t h e RF c o n t r o l l e r t o code i n f o r m a t i o n and a c t i v a t e
t h e RF t r a n s m i t t e r .
The coded i n f o r m a t i o n may be r e t r a n s m i t t e d s e v e r a l
times as a redundant checking f e a t u r e .
'The r e c e i v e r p r o v i d e s t h e coded
tones t o a c o n t r o l l e r which decodes i t i n t o a meaningful message.
Each appl i c a t i o n area ( s e c u r i t y , f i r e , gas compressor o p e r a t i o n , e t c .)
r e q u i r e s d i f f e r e n t sensor i n t e r f a c e s t o t h e RF equipment.
Although b o t h
companies were asked t o c o n s i d e r t h e ramp c o n t r o l a p p l i c a t i o n and submit
c o s t estimates, o n l y one company d i d so.
3)
Determine FCC L i c e n s i n g requirements f o r unmanned t r a n s c e i v i n g equ-ipnient .
Volume 5 , T i t l e 47, P a r t 90, o f t h e Code o f Federal I n s t r u c t i o n s c o n t a i n s
a l l t h e requirements f o r telecommunication u t i l i z i n g r a d i o frequency t r a n s missions.
The p e r t i n e n t s e c t i o n s a r e g i v e n i n Appendix B.
5
The ramp c o n t r o l
interconnect utilizing the RF transceiving equipment was within the FCC
regulations.
The system was terqporarily 1 icensed to operate on voice channel (F3)
for secondary signal ing (F2).
If the decision is made to designate the RF
interconnect as a permanent operational tool, then a new license will be
obtained for a splinter frequency that has only secondary signaling. All
other FCC regulations have been met:
a. Transmitter Station has an identification code.
b. Protection circuit blows a fuse when the transmitter has been
on longer than 10 seconds.
c. The silent time between transmissions is adjustable from 10 seconds
to 120 seconds.
4)
Develop field site requirements and document instal 1 ation procedures.
The standards and practices employed by the SDHPT in both the Radio
and Signal Divisions are excellent. Thus the installation of the RF
equipment posed few problems. The antenna at the transmitter site was
elevated to 20 feet on a wooden pole installed by the SDHPT. The receiving
antennas were placed on top of a 10-foot section of 2" diameter steel pipe
to prevent theft. These antennas are similar in appearance to CB mobile
antennas. The encoding/decoding electronics for both the transmitter and
and receivers were enclosed in a weatherproof fiberglass housing suitable
for outside placement. The housing was placed inside a large standup
controller cabinet to provide a secure, controlled environment. Space in
the cabinet is minimal since the TransTronics ramp controller and four loop
amplifiers are in this cabinet. Care must be exercised in routing the
coaxial cable inside the controller cabinet from the transmitter to the
antenna t o prevent induced i n t e r f e r e n c e .
There was concern about t h e
p o s s i b i l i t y o f induced RF causing t h e ramp c o n t r o l l e r t o m a l f u n c t i o n , b u t
no
problems were e v i d e n t .
A l l o t h e r procedures were r o u t i n e l y s e r v i c e d
by t h e SDHPT.
5)
Develop o p e r a t i o n a l guide1 ines, evaul a t i o n procedures and c o l 1e c t
o p e r a t i o n a l d a t a on t h e implemented system.
The o p e r a t i o n a l g u i d e l i n e s f o r t h e RF i n t e r c o n n e c t were governed by
t h e goals t o be achieved by t h e system c o n t r o l concept o f entrance ramp
metering and t h e requirements f o r RF o p e r a t i o n as d i c t a t e d by t h e FCC
regulations.
The system c o n t r o l concept i s t h a t f l o w r a t e s approaching
t h e master l o c a t i o n should determine c o n t r o l l e v e l s f o r upstream s l a v e
u n i t s , provided l o c a l c o n d i t i o n s are n o t more c r i t i c a l .
The f l o w r a t e
sampling t i m e a t t h e master l o c a t i o n should n o t be f a s t e r than t h e response
time o f t h e RF system.
S-ince t h e RF t r a n s m i t t e r must a1 low f o r 1 minute
of s i l e n c e between transmissions.
, the
should be g r e a t e r than once per minute.
ramp c o n t r o l 1e r ' s sampl i n q r a t e
A sampling time o f 1 minute
may cause metering r a t e s t o f l u c t u a t e and r e s u l t i n spasmodic o p e r a t i o n on
the ramps and freeway.
Experience has shown t h a t f o r l o c a l c o n t r o l o p e r a t i o n ,
a 2 minutes sampling r a t e provides adequate responsiveness t o b o t h ramp and
freeway t r a f f i c .
System c o n t r o l o p e r a t i o n should be observed a f t e r t h e
RF i n t e r c o n n e c t i s i n s t a l l e d t o determine t h e sampl i n g p e r i o d a t t h e master
location.
The m e t e r i n g o f t h e upstream s l a v e u n i t s should be observed t o
i n s u r e t h a t t h e system metering l e v e l s p r o v i d e r e s t r i c t i v e c o n t r o l and
l o c a l metering 1eve1 s respond t o 1ocal c o n d i t i o n s .
During t h e c a l ib r a t i o n
o f t h e systems c o n t r o l , t h e o p e r a t i o n o f t h e RF i n t e r c o n n e c t should n o t be
n o t i c e a b l e ; i.e.
, t h e r e c e p t i o n o f t h e M a s t e r ' s c a l l s f o r metering l e v e l s
7
a t t h e sTave u n i t s should be j u s t as though t h e master were s i t t i n g
n e x t t o t h e s l a v e and w i r e d d i r e c t l y t o i t .
The o n l y n o t i c e a b l e event
w i l l be t h e t o n e t r a n s m i s s i o n as needed w i t h a minimum o f 1 m i n u t e o f
s i l e n c e between t r a n s m i s s i o n s .
To e v a l u a t e t h e RF o p e r a t i o n a s t u d y p l a n was developed t o c o l l e c t
i n f o r m a t i o n on t h e t y p e o f e r r o r s t o be found i n t h e RF equipment, t o
deterniine t h e i r e f f e c t on system c o n t r o l o p e r a t i o n and t o develop c o r r e c t i v e
a c t i o n s t h a t c o u l d be taken.
The d e s c r i p t i o n o f t h e s t u d y p l a n and r e s u l t s
a r e presented i n t h e f o l l m i n g s e c t i o n s .
6)
Determine t h e maintenance requirements and r e 1 i a b i 1 i t y of t h e imp1 emented
system and prepare a t e c h n i c a l r e p o r t .
I n f o r m a t i o n from an o i l and gas p r o d u c t i o n company i n Texas t h a t used
t h e same equipment suggests t h a t t h e RF t r a n s m i t t e r s w i l l r e q u i r e s e r v i c i n g
one o r two t i m e s p e r y e a r .
No i n f o r m a t i o n was o b t a i n e d on t h e RF r e c e i v e r s
and t h e i r a s s o c i a t e d decoding e l e c t r o n i c s , a l t h o u g h maintenance should be
no worse than t h e t r a n s m i t t i n g equipment.
The SDHPT w i l l document t h e
maintenance a c t i v i t i e s o f t h e system i n Ft. Worth.
Section 3
Study Site Description
Study S i t e D e s c r i p t i o n
The s i t e chosen t o i n s t a l l t h e RF t r a n s c e i v i n g equipment i s on westbound I n t e r s t a t e 30 i n F o r t Worth, west o f t h e c e n t r a l business d i s t r i c t
(CBD) ( F i g u r e 1).
The c r o s s s e c t i o n f o r t h e westbound l a n e s v a r i e s ; t h e r e
a r e t h r e e l a n e s l e a v i n g t h e CBD, a f o u r t h l a n e i s added a t t h e Summit
entrance ramp and dropped a t t h e F o r e s t Park e x i t ramp, and t h e t h i r d l a n e
i s dropped a t t h e Montgomery S t r e e t e x i t ramp and U n i v e r s i t y D r i v e e n t r a n c e
ramps.
The f o u r t h e n t r a n c e ramp i n t h e system serves Montgomery S t r e e t .
A l l f o u r e n t r a n c e ramps f o r Summit, F o r e s t Park, U n i v e r s i t y D r i v e , and
Montgomery have ramp m e t e r i n g c o n t r o l l e r s t h a t o p e r a t e on l o c a l freeway
conditions.
The Montgomery S t r e e t e n t r a n c e ramp was chosen t o be xhe master
l o c a t i o n i n t h e system c o n t r o l scheme, because i f t h e f l o w r a t e i n t h e two-lane
s e c t i o n a t t h e Montgomery e n t r a n c e ramp approaches o r exceeds t h e two-lane
c a p a c i t y f o r a p e r i o d o f t i m e t h e freeway o p e r a t i o n s w i l l breakdown.
The
r e s u l t i n g queueing w i l l send shockwaves upstream towards t h e o t h e r t h r e e
entrance ramps.
With t h e RF t r a n s m i t t e r i n s t a l 1ed a t Montgomery ( F i g u r e 2 )
and t h e r e c e i v e r s a t t h e o t h e r t h r e e entrances, r e s t r i c t i v e m e t e r i n g c o u l d be
employed by t h e s l a v e u n i t s .
T h i s r e s t r i c t i v e m e t e r i n g w i l l reduce t o t a l
demand t o t h e two l a n e s e c t i o n t h e r e b y e n a b l i n g t r a f f i c t o resume smooth
f l o w which r e s u l t s i n g r e a t e r throughput.
The geometric d e s i g n o f t h e
ramp-freeway merging j u n c t i o n a t Summit and Montgomery e n t r a n c e ramps
a r e e x c e l l e n t w i t h l o n g a c c e l e r a t i o n l a n e s and good s i g h t d i s t a n c e s
( F i g u r e s 3 and 4 ) .
Limited acceleration lanes are provided a t the other
two entrance ramps.
When freeway speeds d r o p and t h e freeway queue has
formed i n t h e area o f t h e l a n e drop a t Montgomery, freeway t r a f f i c
c o n c e n t r a t e s i n t h e i n s i d e two lanes.
A f t e r t h e t r a f f i c e n t e r s t h e two-
l a n e s e c t i o n , speeds i n c r e a s e and t h e d r i v e r s a r r a n g e t h e i r d e s i r e d headway
RF Study S i t e 1-30
SDHPT D i s t r i c t 2 Headquarters
F i g u r e 1.
Study S i t e
- 1-30 F o r t Worth
spacing.
The ramp t r a f f i c e n t e r i n g t h e two l a n e s e c t i o n a t U n i v e r s i t y
D r i v e and Montgomery S t r e e t ramps cause f u r t h e r adjustments t o be made
i n t h e headway spacings.
I f t h e f l o w r a t e i s t o o h i g h , t h e freeway t r a f f i c
w i l l begin t o slow i t s speed and queueing begins a g a i n .
The system c o n t r o l
concept i s t o m a i n t a i n t h e maximum s t e a d y - s t a t e f l o w r a t e i n t h e two-lane
s e c t i o n by l i m i t i n g t h e e n t r a n c e ramp t r a f f i c .
The t y p i c a l peak p e r i o d extends f r o m 4:30 PM u n t i l 5:30 PM.
a r e two peaking demand p a t t e r n s ; t h e f i r s t peaks around 4:45
There
dropping o f f
u n t i l a n o t h e r s t a r t s j u s t b e f o r e 5:00 PM t h a t peaks around 5:15 PM.
Section 4
Equipment D e s c r i p t i o n
EQUIPMENT DESCRIPTION
The t r a n s c e i v i n g equipment s e l e c t e d f o r t h i s i n s t a l l a t i o n has been
used f o r many y e a r s i n o t h e r a p p l i c a t i o n s as a s t a t u s r e p o r t i n g system
t h a t m o n i t o r s and a u t o n i a t i c a l l y r e p o r t s changes from remote l o c a t i o n s t o a
central site.
receiver.
The two major components o f t h i s system a r e t h e t r a n s m i t t e r and
The t r a n s m i t t i n g d e v i c e i s f u n c t i o n a l l y composed o f 1 ) a s e r i e s
o f m o n i t o r i n g c i r c u i t s t h a t d e t e c t s a c h a u g e - i n - s t a t e o f some e x t e r n a l
process, 2 ) e l e c t r o n i c components designed t o generate coded i n f o r m a t i o n
about t h e monitored process, 3 ) a r a d i o t r a n s m i s s i o n c i r c u i t and 4 ) a
p r e c i s e r a d i o frequency generator t h a t modulates a c a r r i e r s i g n a l
based on t h e coded i n p u t i n f o r m a t i o n .
The modulated s i g n a l i s a m p l i f i e d
and f e d i n t o t h e antenna f o r r a d i a t i o n .
The r e c e i v i n g d e v i c e b a s i c a l l y
reverses t h i s process by 1 ) amp1 i f y i n g t h e r e c e i v e d r a d i o s i g n a l v i a
a tuned c i r c u i t t h a t employs e l e c t r o n i c s and a c r y s t a l e x c i t a b l e f o r
t h e same p r e c i s e frequency as produced by t h e t r a n s m i t t e r , 2 ) c o n v e r t i n g
t h e modulated a u d i o s i g n a l i n t o coded i n f o r m a t i o n , and 3 ) o u t p u t t i n g t h e
s t a t u s o f t h e monitored process based on t h e coded i n f o r m a t i o n .
The
general s p e c i f i c a t i o n s o f t h e t r a n s c e i v i n g equipment a r e g i v e n i n Table 1
a l o n g w i t h i n f o r m a t i o n about t h e thermographic p r i n t e r t h a t p r o v i d e s a
permanent r e c o r d o f t h e monitored process a t t h e t r a n s m i t t e r l o c a t i o n .
O f f - t h e - s h e l f equipment was secured f o r t h e RF i n t e r c o n n e c t and t h e
component packaging was n o t a l t e r e d .
A l l t r a n s m i t t i n g equipment, w i t h t h e
e x c e p t i o n o f antennas, i s c o n t a i n e d i n a f i b e r g l a s s housing s u i t a b l e f o r
outdoor employment.
The power source f o r a l l e l e c t r o n i c s i n t h e t r a n s -
m i t t e r i s s u p p l i e d by a DC s t o r a g e b a t t e r y pack.
Since AC power i s
a v a i l a b l e i n t h e ramp c o n t r o l l e r c a b i n e t , a DC t r i c k l e c h a r q i n q c i r c u i t
was added by t h e RF vendor t o i n s u r e t h a t f u l l DC power i s always
TABLE 1.
General S p e c i f i c a t i o n s o f RF Equipment
TRANSMITTER
POWER:
1 2 VDC s u p p l i e d b y s e a l e d l e a d c a l c i u m b a t t e r i e s .
OPERATING VOLTAGE:
CURRENT DRAIN:
10.5 VDC M i n 14.5 VDC Max.
15-20 microamperes
a t 2 5 ' ~ (100.~A a t 65'~) i n the
p r e a l a r m " m o n i t o r " mode. 400 VA p e r a l a r m c l o s u r e i n t h e
p o s t a l a r m mode. 600 m i l l a m p e r e s (MA) d u r i n g a l a r m t r a n s mission.
POWER DEPLETION:
A p p r o x i m a t e l y 0.05 AH p e r a l a r m c y c l e .
-30'~ t o 6 5 ' ~ ( - 2 2 ' ~ t o 149'~).
OPERATING TEMPERATURE:
ENCODER SIGNALING:
ALARM CYCLE:
B i n a r y 3 t o n e f r e q u e n c y s h i f t k e y i n g (FSK), 1020 Hz
c e n t e t " C L 0 C K " . 8 2 0 Hz "ZERO" and 1220 Hz "ONE".
signa1;ng
a t 16 b i t s p e r second.
One o r 2 t w e n t y b i t messages send (REDUNDANT) p e r t r a n s m i s s i o n . One sync b i t , 7 b i t s s t a t i o n a d d r e s s and 4, 8 o r
12 s t a t u s p o i n t s s e n t p e r message. One, t h r e e o r f i v e
t r a n s m i s s i o n s p e r a l a r m a t 10 t o 1 2 0 seconds i n t e r v a l s
(adjustable).
P a r a l l e l i n p u t s sensing switched low o r d r y c o n t a c t c l o s u r e
w i t h a common r e t u r n and a maximum 20,000 ohms l o o p r e s i s t a n c e .
ALARM INPUT:
FREQLIENCY:
151.055 MHz
50.0005% ( - 3 0 ' ~ t o +60°c).
FREQUENCY STABILITY:
RF POWER OUTPUT:
EMISSION TYPE:
8 W @ 12.5 VDC.
15F2, 16F3.
POWER SUPPLY VOLTS:
t 1 2 . 5 VDC+15% n o m i n a l .
POWER SUPPLY CURRENT:
1.8 Amps @ 12.5 VDC.
AUDIO INPUT IMPEDANCE:
4,700 ohms @ 1 kHz.
ALIDIO INPUT LEVEL @ 1 kHz FOR +3.3 kHz DEVIATION:
AUDIO RESPONSE (300-3000 H z ) :
AUDIO DISTORTION (MAX):
FM HUM & NOISE:
HOUSING:
+ I , -3dB o f s t d . E I A 6 d B / o c t a v e p r e - e m p h a s i s
characteristic.
6% @ 2/3 r a t e d s y s t e m d e v i a t i o n w i t h l k H z m o d u l a t i o n .
60dB b e l o w c a r r i e r .
DUTY CYCLE (W/O DEGRADATION):
DIMENSIONS:
7 mV rms.
50dB b e l o w 2/3 r a t e d s y s t e m d e v i a t i o n .
SPURIOUS & HARMONICS:
WEIGHT:
T r i c k l e charged.
10% (max t r a n s m i s s i o n 1 m i n u t e ) .
16" h i g h , 14" wide, 6" o i e p .
26 l b s . NET, 3 1 l b s . GROSS
F i b e r g l a s s e n c l o s u r e i s o i l , w a t e r , and d u s t p r o o f w i t h s t a i n l e s s
s t e e l h i n g e s and c l a s p .
TABLE 1 (CONTINUED).
General S p e c i f i c a t i o n s o f RF Equipment
RECEIVER-MONITOR
I
POWER:
-
121 VAC
+
20%, 60 cps.
AUDIO INPUT SENSITIVITY:
-18 db t o +18 db (97 M i l l i v o l t s t o 6.2 v o l t s RMS).
S i n s l e c o n v e r s i o n w i t h f i x e d suuelch. ( B e s t
o p e r a t i o n w i t h 0 db t o 18 db s i g n a l s t r e n g t h . )
I
INPUT IMPEDANCE:
1
I
=:
10,000 ohms, b r i d g i n g D.C. Blocked.
6 db ( n o i s e 300-3000 Hz, 6 db/octave power, e q u i v a l e n t FM s q u e l c h
noise).
DECODER SIGNALING:
FREQUENCY:
B i n a r y t h r e e t o n e FSK, 1020 Hz "CLOCK", 820 Hz "ZERO",
1220 Hx "ONE" f r e q u e n c i e s a t 16 b i t s p e r second.
151.055 MHz.
FREQUENCY STABILITY:
SENSITIVITY:
+0.001% (-30°c
0.35pV: 12 dB SINAD
0.5 pV: 20 dB Q u i e t i n g .
SPURIOUS & IMAGE REJ.:
70 dB below c a r r i e r .
NOISE SQUELCH SENSITIVITY:
ADJ. CHANNEL REJECTION:
MODULATION ACCEPTANCE:
AUDIO OUTPUT POWER:
RF INPUT IMPEDANCE:
WEIGHT:
80 dB (20 dB Q u i e t i n g ) .
+7 kHz.
25 ohms r e s i s t i v e .
50 ohms nominal.
Continuous.
OPERATING TEMPERATURE:
DIMENSIONS:
0.25 pV.
500 MW @ < l o % d i s t o r t i o n . '
AUDIO OUTPUT IMPEDANCE:
DUTY CYCLE:
t o +60°c).
0 t o 50'~.
H e i g h t 8"; Width 17%'; Depth 9-7/8".
19 1 bs gross, 11 l b s n e t .
PRINTER
POWER:
117 VAC f 20 %, 60 Hz.
AUDIO INPUT SENSITIVITY:
I
INPUT IMPEDANCE:
I
-
SINAD:
-18 db t o +18 db (97 mv t o 6.2 v o l t s RMS).
c o n v e r s i o n w i t h f i x e d squelch.
15K ohms, b r i d g i n g , D.C.
Single
Blocked.
6 db ( n o i s e 300 - 3000 Hz, 6 d b / o c t a v e power spectrum, e q u i v a l e n t
FM squelch n o i s e ) .
DECODER SIGNALING:
B i n a r y t h r e e t o n e FSK, 1020 Hz c e n t e r "CLOCK", 820 Hz
"ZERO" and 1220 Hz "ONE" f r e q u e n c i e s a t 16 b i t s p e r second.
RECORDING FEATURES:
Thermographic paper (1-3/4 i n c h e s wide and 150 f e e t l o n g ) .
Up t o 128 t r a n s m i t t e r s t a t i o n addresses w i t h a maximum o f
12 m o n i t o r p o i n t s p e r s t a t i o n . Twenty-four hour m i l i t a r y
time notation.
OPERATING TEMPERATURE:
DIMENSIONS:
WEIGHT:
OOC
t o 40'~.
17.9" l o n g , 16.5" wide, 5.25" h i g h .
21 l b s .
available.
The DC power source cannot be e l i m i n a t e d w i t h o u t r e d e s i g n i n g
t h e t o t a l t r a n s m i t t e r package.
Whereas t h e t r a n s m i t t e r can be s t a t i o n e d
a t any remote p o i n t w i t h i t s DC power source, t h e r e c e i v e r m o n i t o r must
o p e r a t e f r o m AC which i s a v a i l a b l e a t a l l s l a v e c o n t r o l l e r s t a t i o n s .
There i s a standby NICAD b a t t e r y pack i n t h e r e c e i v e r u n i t t h a t enables
memory r e t e n t i o n and update d u r i n g AC power f a i l u r e .
I f a monitored
process changes d u r i n g AC power f a i l u r e , t h e change wi 11 be presented
a f t e r AC r e s t o r a t i o n .
Both t h e r e c e i v e r and t r a n s m i t t e r e n c l o s u r e s can
be p l a c e d i n s i d e t h e p r e s e n t l a r g e r t y p e c o n t r o l l e r c a b i n e t s .
One a d j u s t m e n t t o t h e t r a n s m i t t t i n g equipment was made a f t e r t h e i n s t a l l a t i o n and t e s t so a s t o meet t h e FCC r e g u l a t i o n o f a maximum 2 seconds o f t r a n s m i s s i o n (See Appendix B, S e c t i o n 90.235(4)).
The coded i n f o r m a t i o n i s s e n t by
t h e t r a n s m i t t e r a t a r a t e o f 16 b i t s p e r second.
i s t h e l a r g e s t message t h a t can be s e n t .
Twenty b i t s o f i n f o r m a t i o n
M o n i t o r i e d p o i n t s a r e added i n
groups o f 4 p o i n t s ( o r b i t s ) t o t h e group w i t h a maximum o f 3 groups o r
12 b i t s .
A 20 b i t message w i l l have 12 m o n i t o r e d p o i n t s .
The r e m a i n i n g
8 b i t s o f i n f o r m a t i o n i s composed o f one b i t f o r sync and 7 b i t s f o r t h e
s t a t i o n address.
The d e l i v e r e d t r a n s m i t t e r equipment was i n s t r u m e n t e d
w i t h 8 b i t s of i n f o r m a t i o n .
One message l e n g t h i s t h e r e f o r e 16 b i t s ( 1
sync p l u s 7 address p l u s 8 i n f o r m a t i o n ) l o n g and would t a k e 1 second t o
transmit.
The t i m i n g c i r c u i t s i n t h e d e c o r d e r p o r t i o n o f t h e r e c e i v e r s
must have s u f f i c i e n t t i m e t o be a c t i v a t e d b e f o r e message a r r i v a l , t h e r e f o r e
a "porch" i s b u i l t o n t o t h e f r o n t of t h e message.
The c a r r i e r f r e q u e n c y
i s p r e s e n t 50 m i l l i s e c o n d s b e f o r e t h e a r r i v a l o f t h e sync b i t and remains
on t h e same l e n g t h o f t i m e a f t e r t h e l a s t b i t o f i n f o r m a t i o n i s s e n t .
method i s used t o t r i g g e r t h e decoding sequencing.
This
The t o t a l message
t r a n s m i s s i o n t i m e i s t h e r e f o r e l o n g e r t h a n 1 second w i t h t h e added t i m i n g s .
W i t h no a d j u s t m e n t t o t h e t r a n s m i t t i n g equipment, two complete messages a r e
sent each time a monitored point changes thus a total transmission time in
excess of a 2-second duration. The FCC regulations allow for 3 or 5
repetitions of each message for redundancy. With an interval adjustment
to the transmitter enabling only one message to be sent in less than
two seconds, it can be repeated two more times without violating the
regulations. Therefore, in the regular day to day operation, only one
message is sent by the transmitter each time a monitored point changes.
This message is then repeated twice more as a redundancy check.
Section 5
T e s t Theory
THE TEST THEORY
The t e s t i n g o f t h e RF i n t e r c o n n e c t system was t o s a t i s f y t h e b a s i c
question, c o u l d t h e RF equipment p e r f o r m i n l i e u o f a d i r e c t w i r e l i n e
interconnect?
For t h i s t e s t , a RF system was i n s t a l l e d a c c o r d i n g t o
s p e c i f i c a t i o n s developed by t h e T r a f f i c Engineering S e c t i o n o f D i s t r i c t
2 o f t h e SDHPT w i t h t e c h n i c a l s u p p o r t from F i l e D-18T and TTI.
The t o t a l
system was i n s t a l 1 ed and d e c l a r e d o p e r a t i o n a l i n e a r l y January, 1981
.
A
t e s t sequence was d e v i s e d t o r e q u i r e as many messages t o be t r a n s m i t t e d
as p o s s i b l e i n a s h o r t p e r i o d o f t i m e .
Other c o n d i t i o n s o f t h e t e s t
were t h a t 1 ) t h e t e s t i n g should occur w i t h i n t h e normal peak t r a f f i c
demand p e r i o d s (6:30 AM t o 8:30 AM; 4 PM t o 6 PM) and one midday p e r i o d ,
2 ) a minimal number o f e l e c t r o ~ n e c h a n i c a l changes would be made t o t h e
ramp c o n t r o l l e r / R F equipment t o i n i t i a t e and t e r m i n a t e t h e t e s t sequence
and 3 ) human observers would be used f o r message v e r i f i c a t i o n .
The e r r o r s
and t h e i r sources were t o be analyzed and c o r r e c t e d i f p o s s i b l e d u r i n g t h e
t e s t sequence.
TEST PROGRAM
To c r e a t e as many messages as p o s s i b l e w i t h t h e e x i s t i n g equipment, a
s p e c i a l t e s t program was i n s t a l l e d i n t h e ramp c o n t r o l l e r ' s microcomputer.
The p r e s e n t ramp c o n t r o l l o g i c r e q u i r e s l e s s t h a n 1024 b y t e s o f programmable
read o n l y memory (PROM).
bytes o f memory.
The PROM s i z e used by t h e s u p p l i e r c o n t a i n s 2048
I n t h e o t h e r " h a l f " o f PROM, t h e suppl i e r n o r m a l l y places
t e s t programs f o r t h e i r use d u r i n g equipment and ramp c o n t r o l program
checkout p r i o r t o d e l i v e r y t o t h e SDHPT.
A r e q u e s t was made t o t h e ramp
c o n t r o l l e r suppl i e r t o p r o v i d e a s p e c i a l program t h a t c o u l d " e x e r c i s e " t h e
RF equipment a t t h e h i g h e s t r a t e p e r m i s s i b l e .
A RF t e s t program was
designed, programmed and i n s t a l l e d i n t h e t r a n s m i t t e r a t t h e Montgomery
S t r e e t ramp c o n t r o l l e r .
The normal ramp c o n t r o l l o g i c i s documented by t h e s u p p l i e r ' s manual
of o p e r a t i o n s .
The f r o n t a l f a c e o f t h e ramp c o n t r o l l e r ( F i g u r e 5 ) c o n t a i n s
1amps t h a t p r o v i d e a p o s i t i v e v e r i f i c a t i o n o f some occurrence: i.e. segmenter
1eve1 , a d e t e c t o r being occupied, e t c .
A1 so, t h e c e n t r a l p r o c e s s i n g u n i t ,
CPU, program module c o n t a i n s p i n s l o t s f o r v a r i o u s ramp c o n t r o l program
o p t i o n s as w e l l as i t s mode o f o p e r a t i o n .
The i n t e r p r e t a t i o n o f t h e lamps
and p i n s l o t s d i r e c t l y r e f l e c t t h e program l o g i c t h a t i l l u m i n a t e s t h e lamps
and renders values t o t h e p i n s l o t s .
By changing t h e program l o g i c ( f r o m
ramp c o n t r o l t o RF t e s t ) , t h e f r o n t face must be r e - i n t e r p r e t e d as
shown i n F i g u r e 6.
The RF t e s t l o g i c programmed i n t o t h e second h a l f o f t h e PROM r e f l e c t s
t h e d e s i r e d t e s t o p e r a t i o n (as many messages as p o s s i b l e ) b u t i s r e s t r a i n e d
by t h e o p e r a t i o n a l modes of t h e RF t r a n s m i t t e r .
Appendix C c o n t a i n s a
d e s c r i p t i o n o f t h e e x t e r n a l i n p u t s and o u t p u t s f r o m t h e ramp c o n t r o l l e r .
The f o u r v e h i c l e presence d e t e c t o r o u t p u t s were s e l e c t e d t o p r o v i d e t h e
p o i n t s t o be monitored by t h e f i r s t f o u r - b i t group o f t h e RF equipment.
I f anyone o f t h e f o u r p o i n t s change s t a t e s ( " O H - o f f and "1"-on) t h e n a new
message must be t r a n s m i t t e d (because t h e t r a n s m i t t e r l o g i c i s w i r e d i n
t h i s manner).
The RF t e s t l o g i c begins by r e a d i n g t h e c o n d i t i o n o f f o u r
p i n s l o t s of Group 1 ( G l ) on t h e CPU module board ( F i g u r e 6 ) .
s l o t has been pinned, a "1" o r "on" r n n d i t i o n i s s e t .
If a pin
The RF equipment
c o n s t a n t l y l o o k s a t these f o u r p o i n t s as presented by t h e RF t e s t (ramp)
controller.
The RF t r a n s m i t t e r n o t i f i e s t h e t e s t program t h a t i t has s e n t
t h e l a s t message and i s now ready f o r t h e n e x t message.
The RF t e s t program
/
-
>
@
0
DISPLAY
A
0
QUEUE
I O .
1
0 l
I
O
I
% 8
0 4
1 1 0 1
32 0 11
14 012
F i g u r e 5.
I /O
POWER SUPPLY
'IMER
SL
fREEWAY OCCUPANCY
Molt: o=o. O O ~ l O O
TEST
CPU
QUEUE
5
0 1 0
o l o s
O
I
O
0 1 0 : ,
0 1 1 0
011 0
0
F r o n t a l Face o f RIYC-3 Ramp C o n t r o l l e r
CPU
MERGE
1
2
0
1-
FRWY
.5 0
'
4
64 0 1 3 2
E
E
n
I YELLOW
1 1
E4
1
I
01
=I.
M O D E O f OPERATION
0CLOCK
2 0CLOCK
+ +'NOT L E V E L
A'
0S E G M E N T L R
4 0S E C M E I I T L R + C L O C K
3
I
CODE:
SL=SEGMEUTER
IPIRLIIITI
LEVEL
During Ramp Control
During RF T e s t
F i g u r e 6. CPU Panel Module Assignments a t T r a n s m i t t e r S i t e
then reads Group 2 and t h e RF t r a n s m i t t e r a g a i r r e s p o n d s by sending and
c l e a r i n g f o r another message.
The RF t e s t program c o n t i n u e s i n t h i s
manner u n t i l a l l 15 groups have been r e a d and s e n t .
t o Group 1 a s i x t e e n t h group i s s e n t .
Before r e v e r t i n g back
One o p e r a t i o n a l f e a t u r e of t h e RF
t r a n s m i t t e r i s t h a t no new liiessage w i l l be s e n t u n l e s s i t i s d i f f e r e n t
t h a n t h e l a s t message s e n t .
As programmed, no new message w i l l be made
a v a i l a b l e by t h e RF t e s t program unless t h e l a s t message i s s e n t and c l e a r e d
by t h e RF t r a n s m i t t e r .
runaway.
T h i s "handshaking" l o g i c p r e v e n t s a RF t e s t l o g i c
Due t o t h i s handshaking f e a t u r e , . i t i s i m p e r a t i v e t h a t t h e
message c o n t e n t o f each group (GI-G15) be d i f f e r e n t f r o m i t s predecessor.
Table 2 p r e s e n t s a t y p i c a l RF t e s t d a t a s e t .
Before t h e l a s t two s l o t s on t h e Mode o f O p e r a t i o n a l a r e pinned f o r
TEST ( F i g u r e 6 ) , each group must be pinned as p e r t e s t d a t a s e t .
During
each t i m e p e r i o d , t h e r e were seven d a t a s e t s each d i f f e r e n t i n t h e o r d e r
and makeup o f each group.
Each d a t a s e t was s e n t f o u r times, i . e . Groups
1-15 were c y c l e d f o u r times b e f o r e a n o t h e r d a t a s e t was pinned.
As shown
i n F i g u r e 7, an observer' i s p i n n i n g a new d a t a s e t .
While t h e ramp c o n t r o l l o g i c had t o be bypassed a t t h e t r a n s m i t t e r
s i t e because o f t h e RF t e s t program, ramp c o n t r o l l o g i c was e n f o r c e a t t h e
receiver sites.
The o n l y changes t h a t had t o be made were f o r t h e f o u r
b i t s o f i n f o r m a t i o n b e i n g monitored, s e n t and r e c e i v e d t o bemade a v a i l a b l e
t o t h e f r o n t a l f a c e o f t h e ramp c o n t r o l l e r i n a convenient l o c a t i o n .
Since
t h e f o u r d e t e c t o r s were used a t t h e t r a n s m i t t e r s i t e , a s p e c i a l w i r i n g bypass harness was implemented by D i s t r i c t 2 a t a l l t h r e e s l a v e u n i t s .
This
bypass enabled t h e observer t o see t h e f o u r b i t s r e c e i v e d on t h e f o u r lamps
l a b e l e d under D e t e c t o r s ( F i g u r e 8 ) .
Table 2.
Date
17Feb 81
T y p i c a l T e s t Data Set
Tues
Time P e r i o d
PM
1 = Pinned
0 = Unpinned
Time S t a r t
I
G1
I
0
0 ' 0
0
66
1 1 ! 1
1
1
0
Gll
1
0 0 . 0
Figure 7.
New Data Set Being Pinned.
I
DISPLAY
/
GROUP
DISPLA'Y
TEST
0RESET
0HALT
Ramp C o n t r o l
F i g u r e 8.
RF T e s t
D i s p l a y Panel Module D e f i n i t i o n s a t Receiver S i t e s
A TYPICAL TEST SEQUENCE
As each o f t h e f o u r observers a r r i v e d t o t h e i r r e s p e c t i v e l o c a t i o n s ,
t h e r e was v o i c e communication c o n t a c t w i t h each o t h e r v i a hand h e l d w a l k i e t a l k i e s o p e r a t i n g on a d i f f e r e n t frequency t h a n t h e RF i n t e r c o n n e c t .
The
s l a v e l o c a t i o n observers would employ t h e bypass c o n n e c t i o n and p i n t h e
ramp c o n t r o l l e r t o keep t h e ramp s i g n a l s f r o m i n a d v e r t e n t o p e r a t i o n .
Before t h e f i r s t message i s sent, t h e observer a t t h e master s i t e ( t r a n s m i t t e r ) n o t i f i e s each s l a v e as t o which d a t a s e t i s used.
Each s l a v e
l o c a t i o n has a copy o f each group i n each d a t a s e t f o r v e r i f i c a t i o n .
A f t e r t h e RF t e s t i s i n i t i a t e d and group sequencing has begun, l i t t l e
v o i c e communication i s r e q u i r e d .
The master l o c a t i o n observer n o t i f i e s
each s l a v e l o c a t i o n a t t h e s t a r t o f a new d a t a s e t ( F i g u r e 9 ) .
To keep
t h e s l a v e observers f r o m becoming u n a t t e n t i v e , t h e observer a t t h e master
l o c a t i o n w i l l change a group makeup f r o m t h e i n t e n d e d message t h u s c r e a t i n g
an " a r t i f i c i a l e r r o r " f o r t h e s l a v e observers.
A t t h e D i s t r i c t 2 head-
q u a r t e r s t h e thermographic p r i n t e r p r o v i d e d a hard copy documentation
o f a l l messages r e c e i v e d f r o m t h e t r a n s m i t t e r .
Section 6
The Test Sequence
THE TEST SEQUENCE
As each observer a r r i v e d a t t h e i r r e s p e c t i v e l o c a t i o n , t h e c o n t r o l l e r
c a b i n e t was opened and t h e m a t e r i a l s t o r e c o r d t h e t e s t r e s u l t s were r e a d i e d .
The s l a v e l o c a t i o n observers had t o employ t h e bypass c o n n e c t i o n and program
t h e ramp c o n t r o l l e r t o i n h i b i t t h e e n t r a n c e ramp s i g n a l s f r o m o p e r a t i n g
during the test.
The observer a t t h e master s i t e stopped t h e ramp
c o n t r o l l e r w h i l e t h e t e s t d a t a s e t was prograrnn~ed. The master s i t e observer
would i n i t i a t e v o i c e c o n t a c t w i t h each s l a v e s i t e observer o v e r hand h e l d
r a d i o s t h a t operated on a d i f f e r e n t frequency t h a n t h a t err~ployed by t h e
RF system.
When a l l was ready, t h e master s i t e observer would n o t i f y t h e s l a v e
s i t e s as t o t h e d a t a s e t t o be s e n t .
The observer a t t h e master s i t e would
then i n i t i a t e t h e RF t e s t program c o n t a i n e d w i t h i n t h e ramp c o n t r o l l e r ' s
memory.
Each s l a v e l o c a t i o n observer was p r o v i d e d a copy o f t h e d a t a s e t
for verification.
A f t e r t h e RF t e s t was i n o p e r a t i o n and automatic group
sequencing had begun, l i t t l e v o i c e communication was r e q u i r e d .
As t h e
l a s t r e p e a t o f t h e d a t a s e t was b e i n g sent, t h e observer a t t h e master s i t e
would i n s t a l l t h e n e x t d a t a s e t .
The observers a t t h e s l a v e s i t e s were
n o t i f i e d when t h e f i r s t group o f a new d a t a s e t was s e n t so t h a t t h e proper
v e r i f i c a t i o n c o u l d be made ( F i g u r e 9 ) .
Each d a t a s e t c o n t a i n e d s i x t e e n
d i f f e r e n t groups and was repeated f o u r times.
Each s l a v e observer had t o
check off t h e s u c c e s s f u l ( o r unsuccessful) r e c e p t i o n o f t h e v a r i o u s groups
w i t h i n each d a t a s e t .
To keep t h e s l a v e observers from becoming u n a t t e n t i v e ,
t h e observer a t t h e master l o c a t i o n would d e l i b e r a t e l y change a group makeup
from t h e i n t e n d e d message p r o v i d e d on t h e v e r i f i c a t i o n sheets.
an " a r t i f i c i a l e r r o r " f o r t h e s l a v e observers t o r e c o r d .
T h i s provided
T h i s process
continued u n t i l a l l seven d a t a s e t s were programmed, sent and r e c e i v e d .
Figure 9. New Data Set--Initial Transmission.
While each s l a v e observer was v e r i f y i n g t h e r e c e i v e d RF message, t h e
same RF s i g n a l was b e i n g r e c e i v e d a t t h e D i s t r i c t 2 headquarters.
The
thermographic p r i n . t e r p r o v i d e d a copy o f t h e r e c e i v e d messages s e n t from
t h e master l o c a t i o n ( t r a n s m i t t e r )
.
By comparing t h e messages programmed
by t h e master observer w i t h t h e v e r i f i e d messages recorded a t t h e s l a v e
s i t e s and t h e D i s t r i c t 2 p r i n t e r tapes, any e r r o r s c o u l d be found and
analyzed.
Section 7
The T e s t
THE TEST
The RF t e s t was conducted t h e week o f February 16-20, 1981.
A
p r e l i m i n a r y t r i a l r u n was scheduled f o r Monday a f t e r n o o n , February 16, 1981.
The personnel were d i s p e r s e d t o t h e i r r e s p e c t i v e l o c a t i o n s f o r a t r i a l
p e r i o d o f becoming f a m i l i a r w i t h t h e equipment and d e t e r m i n i n g m o d i f i c a t i o n s
o f t h e t e s t i n g sequence.
Approximately one hour o f f u l l s c a l e t e s t o p e r a t i o n
was conducted w i t h o u t e r r o r s .
A l l ramp c o n t r o l s e t t i n g s were r e i n s t a t e d a t
t h e c l o s e o f t h e t r i a l t e s t (as t h e y were a t t h e c l o s e o f e v e r y t e s t p e r i o d )
t o t h e i r p r i o r settings.
The RF t e s t i n g began Tuesday, February 17, 1981 a t 6:30 AM.
o f each t e s t p e r i o d i s i n c l u d e d i n Appendix D.
log
The e a r l y AM peak p e r i o d s
were c h a r a c t e r i z e d as b e i n g moderately cool b u t t h e temperature warmed up
i n t h e midday and PM peak p e r i o d s .
Emphasis was placed on o b s e r v i n g t h e
p o i n t s i n t i m e when outdoor a d v e r t i s i n g l i g h t i n g , freeway i l l u m i n a t i o n ,
e t c . were changing.
There was concern t h a t s p u r i o u s RF emission from these
outdoor sources m i g h t p r o v i d e i n t e r f e r e n c e t o t h e r e c e p t i o n o f t h e t r a n s m i t t e d
s i g n a l s , b u t n o t i n t e r f e r e n c e was observed.
While t h e h i g h band frequency (151.055 MHz) assigned t o t h e ramp m e t e r i n g
i n t e r c o n n e c t i s n o t used w i t h i n D i s t r i c t 2, i t i s used f o r v o i c e communication
i n t h e a d j a c e n t D i s t r i c t 18 ( D a l l a s ) .
Infrequently, portions o f voice
conversations would be p i c k e d up by t h e RF r e c e i v e r s a t t h e s l a v e l o c a t i o n s .
Though t h e s i g n a l s were weak, s u f f i c i e n t energy remained a c t i v a t i n g t h e
receivers.
The v o i c e modulations d i d n o t c o n t a i n t h e c o r r e c t f r e q u e n c i e s
and t i m i n g p a t t e r n s t o a c t i v a t e t h e decoder c i r c u i t s .
The RF s i g n a l when t r a n s -
m i t t e d from t h e Montgomery S t r e e t e n t r a n c e ramp l o c a t i o n superceded a l l o t h e r
s i g n a l s a t t h e assigned frequency because o f s i g n a l s t r e n g t h (power) and t h e c l o s e ness o f t h e r e c e i v e r s t o t h e t r a n s m i t t e r .
Even w i t h s i g n a l s o f equal s t r e n g t h ,
t h e decoding c i r c u i t s would n o t a c t i v a t e unless t h e " f r o n t porch" o f t h e
c e n t e r tone was present f o r t h e e x a c t r e q u i r e d time.
The c o n t r o l l e r s were c a r e f u l l y monitored f o r induced i n t e r f e r e n c e
between t h e t r a n s m i t t e r and ramp c o n t r o l l e r , b u t none was observed.
Adequate
p r o t e c t i o n of c i r c u i t s , packaging methods and good i n s t a l l a t i o n procedures
r e s u l t e d i n t h i s e l e c t r o n i c a l l y "clean" i n s t a l l a t i o n .
I n t h e RF t e s t , t h e t r a n s m i t t e r and i t s c o n t r o l l e r repeated two
complete 16 b i t messages t h r e e times.
A t t h e end o f t h e t h i r d repeat, t h e
"handshake1' between t h e RF d e v i c e and t h e RF t e s t program c o n t r o l l e r would
occur.
Then a new message would be presented t o t h e RF c o n t r o l l e r and
another t r a n s m i s s i o n sequence would occur.
A v a r i a t i o n i n t h e message
p a t t e r n r e c e i v e d and presented a t t h e s l a v e l o c a t i o n s was observed.
A t the
beginning o f t h e t e s t i n g most new messages were observed t o change on t h e
f i r s t transmission.
L a t e r on i n t h e s t u d i e s , observations o f t h e message
c o n t e n t found changes on t h e second t r a n s m i s s i o n and o c c a s i o n a l l y on t h e
t h i r d (See Appendix D ) .
When t h e message c o n t e n t d i d change, i t conformed
t o t h e expected p a t t e r n ; i . e . what should have been present, was present.
The suspected f a u l t was thought t o be some variance o r maladjustment i n t h e
performance o f t h e decoding c i r c u i t s i n t h e r e c e i v e r s .
I n q u i r i e s made o f
D i s t r i c t 2 personnel, as w e l l as a r e p r e s e n t a t i v e o f t h e RF equipment
s u p p l i e r , suggested t h a t t h e s i g n a l l e v e l i n t o t h e decoding c i r c u i t s was
n o t adequate and a volume adjustment on t h e RF r e c e i v e r would s o l v e t h i s
problem.
As shown i n F i g u r e 10, each RF r e c e i v e r has a volume adjustment.
This
s o l i d s t a t e ( e l e c t r o n i c s ) , s i n g l e conversion r e c e i v e r w i t h a f i x e d squelch
i s commonly used as a v o i c e communication's monitor.
The volume adjustment
i s i n c l u d e d t o v a r y t h e loudness (amp1 i t u d e ) o f t h e r e c e i v e d speech.
I n the
RF RECEIVER WITH
VOLUME
ADJUSTMENT
Figure 10.
RAMP CONTROLLER 4 LAMP INDICATOR
ANNLIN ICATOR ( DECODER)
T y p i c a l Slave U n i t Observation During RF Test.
RF i n t e r c o n n e c t a p p l i c a t i o n , t h e audio i n p u t i n t o t h e decoding c i r c u i t s
was a l s o connected t o t h e o u t p u t s i d e o f t h e volume adjustment as i s t h e
s e l f - c o n t a i n e d speaker.
When t h e observers a t t h e s l a v e l o c a t i o n s opened
t h e c o n t r o l l e r c a b i n e t and p o s i t i o n e d themselves so as t o observe t h e lamp
i n d i c a t i o n s d u r i n g t h e RF t e s t s , i t was sometimes necessary t o a d j u s t t h e
volume on t h e RF r e c e i v e r .
The background freeway t r a f f i c n o i s e , t h e
nearness of t h e c o n t r o l l e r c a b i n e t t o t h e freeway and t h e n e c e s s i t y t o
remain c l o s e t o t h e f r o n t a l f a c e o f t h e ramp c o n t r o l l e r o f t e n r e q u i r e d l a r g e
volume adjustments.
It was necessary f o r t h e observer t o hear t h e audio
tones so t h a t a d e c i s i o n c o u l d be made as t o whether t h e message p a t t e r n
changed on t h e f i r s t , second, o r t h i r d t r a n s m i s s i o n .
It i s p o s s i b l r t o
under o r o v e r d r i v e t h e a u d i o i n p u t s i g n a l t o t h e decoding c i r c u i t s , j u s t
as i t i s p o s s i b l e t o s i m i l a r l y
a f f e c t an a u d i o speaker system.
The
r e s u l t s a r e t h e same; a s i g n a l l e v e l so weak an observer cannot hear, o r
o v e r d r i v e n t o t h e p o i n t where d i s t o r t i o n i s p r e v a l e n t .
I n most cases, t h e
audio s i g n a l had been reduced t o t h e p o i n t where t h e decoding c i r c u i t j u s t
b a r e l y c o u l d "hear" t h e "message".
D u r i n g t h e t e s t i n g o f t h e RF system, t h e
volume was a d j u s t e d so t h a t decoder changes were noted on t h e f i r s t t r a n s mission.
A permanent s o l u t i o n t o t h e adjustment problem would be t o i n s t a l l
a c i r c u i t t h a t p r o v i d e s a c o n s t a n t a u d i o i n p u t s i g n a l l e v e l t o t h e decoder
circuits.
The c o o r d i n a t i o n of human a c t i v i t y proved t o be d i f f i c u l t .
Each observer
had t o compare t h e r e c e i v e d 4 b i t s message w i t h t h e c o r r e c t d a t a s e t and
group number message f o r t h a t d a t a s e t .
contact v i a the walkie-talkies.
I t was i m p r o s s i b l e a t times f o r v o i c e
For i n s t a n c e , U n i v e r s i t y o r F o r e s t Park
l o c a t i o n s would have t o r e l a y v o i c e i n s t r u c t i o n s from Montgomery (master
and t r a n s m i t t e r l o c a t i o n ) t o Summit and back.
t o g e t out-of-sequence.
T h i s caused s e v e r a l observers
It would be s e v e r a l messages b e f o r e t h e observer
would r e a l i z e t h a t t h e r e c e i v e d message was n o t even c l o s e t o t h e expected
message.
The observer would be r e c o r d i n g e r r o r s f o r each case where t h e
r e c e i v e d message was n o t matching t h e expected message.
Knowing t h a t
m u l t i p l e e r r o r s were h i g h l y u n l i k e l y , t h e observer would r e - e s t a b l i s h t h e
o b s e r v a t i o n p o i n t i n t h e d a t a s e t by w a i t i n g f o r t h e i n i t i a l group 1 o r
i n s t r u c t i o n f r o m t h e master l o c a t i o n .
I n a l l cases o f r e - o r i e n t a t i o n , t h e
observer c l e a r l y documented on t h e v e r i f i c a t i o n r e c o r d s as t o when t h e
out-or-sequence began and where c o r r e c t matching t o o k p l a c e .
While t h i s
may appear t o be u n a t t e n t i v e n e s s on t h e observers p a r t , v e r y few o u t - o f sequence occurances a c t u a l l y happened.
Most occurred when t h e observer
had an o u t s i d e i n f l u e n c e such as a h i t c h h i k e r f r o m t h e freeway conversing
w i t h t h e observer.
I n t h e s e cases, n o t o n l y was t h e observer conce-ned
about t h e message p a t t e r n and sequence, b u t a c e r t a i n f e a r f a c t o r f o r
personal s a f e t y t h a t precluded t h e r e l a t i v e importance o f message
observation.
Section 8
Test Results
TEST RESULTS
An o b j e c t i v e o f t h e RF t e s t was t o determine t h e f a i l u r e r a t e o f
t h e i n s t a l l e d RF equipment a c t i n g as a d i r e c t w i r e l e s s i n t e r c o n n e c t and
i t s p o t e n t i a l e f f e c t on t h e ramp c o n t r o l o p e r a t i o n .
Statistical tests
had been devised t o a p p l y t o t h e e r r o r s t h a t were found.
Throughout t h e
RF t e s t s , t h e p r i n t e r a t t h e D i s t r i c t 2 Signal Shop had been r e c o r d i n g a l l
r e c e i v e d messages from t h e master l o c a t i o n .
This record plus the records
from t h e t h r e e o t h e r s l a v e l o c a t i o n s ( U n i v e r s i t y , F o r e s t Park, and Summit)
p r o v i d e d t h e i n f o r m a t i o n t h a t was compared a g a i n s t t h e recorded i n f o r m a t i o n
sent from t h e master l o c a t i o n .
Table 3 i n d i c a t e s t h e t o t a l number o f
t r a n s m i t t e d Iiiessages and b i t s o f i n f o r m a t i o n sent.
Corr~parisons were made
o f i n d i v i d u a l messages s e n t from t h e t r a n s m i t t e r s i t e and r e c e i v e d a t t h e
Signal Shop p r i n t e r .
T h i s comparison was t e d i o u s because t h e p r i n t e r
was e x p e r i e n c i ~ gs p o r a d i c p e r i o d s o f what appeared t o be s e l f - i n d u c e d
messages.
T h i s d i a g n o s i s was l a t e r v e r i f i e d by t h e s u p p l i e r .
These
f a l s e messages were e a s i l y d e t e c t a b l e on t h e p r i n t e r ' s p r i n t o u t because
of n o n - e x i s t e n t s t a t i o n addresses being g i v e n and i n f o r m a t i o n i n t h e
second 4 b i t group ( F i g u r e 11).
None o f these f a l s e messages were used
i n t h e a n a l y s i s because t h e p r i n t e d i n f o r m a t i o n o c c u r r e d w i t h o u t a r e c e i v e d
transmission.
The messages would be p r i n t e d w i t h o u t tones b e i n g heard f r o m
t h e RF r e c e i v e r .
tones.
These f a l s e messages were o c c u r r i n g between t h e r e c e i v e d
Thus, no t r a n s m i t t e d i n f o r m a t i o n was l o s t o r mixed w i t h t h e f a l s e
information.
A l l t r a n s m i t t e d i n f o r m a t i o n was r e c e i v e d and recorded c o r r e c t l y .
D u r i n g each t i m e p e r i o d seven d a t a s e t s of t e s t i n f o r m a t i o n were t r a n s m i t t e d f o u r times.
There were s i x t e e n messages i n each d a t a s e t and each
message c o n t a i n s f o u r b i t s of i n f o r m a t i o n .
As shown i n Table 3, t h e r e
were 3,648 four b i t messages o r 14,592 b i t s o f i n f o r m a t i o n t r a n s m i t t e d
TABLE 3.
RF TEST RESULTS
Period
Tue.
AM
Tue.
NOON
Tue.
PM
Wed.
AM
Wed.
NOON
Wed.
PM
Thur.
AM
Thur.
NOON
TOTALS
Messages
Per Set
Sets
228
*
16
Total
Messages
=
3648
Bits
Per Message
*
4
=
Total
Bits
14,592
F i g u r e 11.
Comparison of Messages a t P r i n t e r S i t e
Messages
Rea 1
Fa1s e
Rea 1
1218
1218
1218
001
062
0001
First 4 Bits
0101
1001
0001
Second 4 B i t s
0000
0111
0000
Time of day
S t a t i o n address
o v e r t h e 3-day t e s t p e r i o d .
A n a l y s i s o f t h e p r i n t e r ' s r e c o r d i n comparison
t o t h e t r a n s m i t t e d p a t t e r n i n d i c a t e d t h a t no
e r r o r s were present.
The
planned s t a t i s t i c a l t e s t s were n o t r u n because w i t h o u t an e r r o r , t h e e r r o r
r a t e r e s u l t s a r e meaning1 ess.
The message p a t t e r n s recorded by t h e observers a t t h e t h r e e s l a v e
l o c a t i o n s d i d n o t compare as w e l l as t h e p r i n t e r ' s r e s u l t s when taken
a t face value.
There were 3 1 cases i n which one o f t h e 4 b i t s i n t h e
r e c e i v e d message d i d n o t match t h e t r a n s m i t t e d message f o r a l l t h r e e
locations.
These e r r o r s r e p r e s e n t a p p r o x i m a t e l y a 0.2% e r r o r r a t e over
t h e t o t a l number o f t r a n s m i t t e d b i t s .
Human e r r o r r a t e s a r e t a s k o r i e n t e d ;
i . e . t h e more t a s k s r e q u i r e d by t h e observer, t h e more chance an e r r o r
w i l l be produced.
Informed soulrces -indicated e r r o r r a t e s o f up t o 5%
a r e n o t uncommon f o r s i m i l a r t a s k s as performed by t h e observers i n t h e
RF t e s t (1).
Therefore, t h e 0.2% e r r o r s recorded by t h e observers c o u l d p r o b a b l y
be a t t r i b u t a b l e t o human e r r o r and n o t t o i n t e r f e r e n c e o r equipment malfunctions.
There were no mu1 t i p l e e r r o r s f o r t h e same b i t a t t h e same
l o c a t i o n o r s i m i l a r e r r o r s by t i m e o f day o r l o c a t i o n .
Since t h e p r i n t e r
d i d n o t r e c o r d an e r r o r and t h e same decoding c i r c u i t s and components were
used i n t h e f o u r r e c e i v e r l o c a t i o n s , i t i s reasonable t o assume t h a t t h e
e r r o r s found by t h e observers were human e r r o r s ; n o t a s s o c i a t e d w i t h t h e
equipment f u n c t i o n s .
What would happen t o t h e ramp c o n t r o l o p e r a t i o n a t t h e s l a v e
l o c a t i o n s i f a f a i l u r e occurred i n t h e RF i n t e r c o n n e c t system?
answers
depend on where t h e f a i l u r e occurred.
The
Table 4 p r e s e n t s t y p e s o f
f a i l u r e s and t h e r e s u l t i n g e f f e c t s on t h e ramp m e t e r i n g o p e r a t i o n .
The most
reasonable r e s u l t s would be cases 2 and 3 where a s l a v e u n i t would c o n t i n u e
t o meter ramp t r a f f i c u n l e s s t h e ramp c o n t r o l l e r has t i m e c l o c k 1 i m i t s .
TABLE 4.
RF I n t e r c o n n e c t F a i l u r e s and System Control f o r Ramp M e t e r i n g A f f e c t .
Case
1.
F a i l u r e Type
AC Power
Fai 1 u r e
- - - - - - - - - - - - - - - - .
2.
AC Power
Failure
- - - - - - - --------..
3.
One o f 3 b i t s
always on
- - - - - - - - - - - - - - - - .
4.
One o f 3 b i t s
always
- - - - - - - - - - - - - -on- . .
5.
One o f 3 b i t s
always o f f
- - - - - - - - - - - - - - - - .
6.
One o f 3 b i t s
always o f f
Failure
Location
Function
Prohibition
Transmitter
No segmenter
1eve1
Results
. . . . . . . . . . . . . . . . . . . .
Sl ave
. . . . . . . . .
(Master)
Transmitter
Received segmenter 1eve1
n o t a v a i l a b 1e
.f o.r .use
. . . . .
. . .
Remote computer
c o n t r o l a1ways
on
. . . . . . . . . . . . . . . . . . . .
S l ave
. . . . . . . . .
Transnii t t e r
. . . . . . . . .
S l ave
(Same as
. case
. . .3).
. . . . . .
Severity o f
segmenter a t
s l a v e never as
g r e a t as should
.be. . . . . . . .
(Same as
case 5 )
Slave u n i t s
r u n on l o c a l
c.o .n d.i t .i o n. s.
No ramp
metering
w i t h o u t AC
power
. . . . . .
R3mp m e t e r i n g
c o n t i nous unless time
clock turns
A.C . power
. . . o.f f
(Same as
.case
. . .3 ) .
.
Ramp m e t e r i n g
c o u l d n o t be
as r e s t r i c t i v e
as should be
. . . . . . . .
(Same as
case 5 )
I n o t h e r cases, t h e system c o n t r o l approach on i n t e r c o n n e c t i n g t h e ramp
metering would n o t be o p e r a t i o n a l .
The 3-day RF t e s t was n o t l o n g enough t o e s t a b l i s h a l o n g term o p e r a t i o n
and maintenance p a t t e r n on t h e equipment.
During t h e normal ramp c o n t r o l
system operations, t h e RF i n t e r c o n n e c t on t h e t e s t s i t e i n F o r t Worth could
r e q u i r e up t o 30 transniissions per c o n t r o l p e r i o d using 2-minute occupancy
averaging f o r segmenter 1eve1 s e l e c t i o n .
I f t h e c o n t r o l p e r i o d averaged
one hour, t h e 3648 transmissions experienced d u r i n g t h e t e s t represents
.approximately 24 weeks ( o r 6 months) o f r u n t i m e w i t h o u t a f a i l u r e .
Based
on s i m i l a r equipment c o n f i g u r a t i o n s i n t h e o i l and gas p r o d u c t i o n i n d u s t r i e s ,
one o f two maintenance c a l l s p e r y e a r i s t h e norm.
D i s t r i c t 2 i s cooperating
i n m a i n t a i n i n g records on t h e i n s t a l l e d RF equipment so t h a t a b e t t e r i n s i g h t
can be e s t a b l i s h e d on t h e equipment f o r t h e s p e c i f i c a p p l i c a t i o n f o r which
i t i s being u t i l i z e d .
Section 9
Cost Comparison
COST COMPARISON
F i r m c o s t f i g u r e s were e s t a b l i s h e d f o r t h e RF i n t e r c o n n e c t system
based on t h e r e c e i v e d b i d quotes and documentation from D i s t r i c t 2.
Table
5 c o n t a i n s these general c o s t s as w e l l as t h e e s t i m a t e d c o s t s f o r a
comparable d i r e c t b u r i a l w i r e 1 i n e i n t e r c o n n e c t .
The comparison g i v e n i n
Table 5 f o r a w i r e l i n e i n t e r c o n n e c t i s f o r d i r e c t b u r i a l o f c a b l e e x t e n d i n g
from Montgomery entrance ramp (master) t o each o f t h e 3 s l a v e l o c a t i o n s .
Crossings o f t h e ramps, r i v e r , and i n t e r s e c t i o n a l b r i d g e s were f i g u r e d based
on u s i n g c o n d u i t fastened t o s u p e r s t r u c t u r e o r b u r i e d v i a j a c k and bore
methods under t h e ramps.
A l l d i s t a n c e f i g u r e s were o b t a i n e d u s i n g ccaled
drawings o f t h e c o n s t r u c t i o n p l a n s a l o n g t h e s t u d y s i t e .
The c o s t p e r
u n i t q u a n t i t y f i g u r e s were gathered from r e c e n t p r i c e quotes f o r urban
p r o j e c t s i n and around t h e Houston area.
A l l costs include i n s t a l l a t i o n .
The q u a n t i t y o f p u l l boxes and o t h e r s p e c i a l hardware r e q u i r e d i n and
around t h e r e c e i v e r s i t e s a r e n o t included.
Whereas t h e w i r e l i n e i n t e r -
connect has t h e added v a l u e o f unencumbered u t i l i z a t i o n , t h e r e i s t h e
t h r e a t o f c a b l e severage due t o maintenance and c o n s t r u c t i o n a c t i v i t i e s .
The d i r e c t b u r i e d c a b l e has l i t t l e maintenance, b u t r e p a i r s due t o
severage i s c o s t l y .
W i r e l i n e i n t e r c o n n e c t v i a leased telephone l i n e s was
n o t considered f o r t h i s a p p l i c a t i o n .
TABLE 5.
System Costs and Estimates
-
RF SYSTEM (ACTUAL COST)
A l l RF equipment
DIRECT WIRELINE (ESTIMATED COST)
$ 11,016.50
1 e x t r a antenna
1 wooden p o l e
3 2"x101 heavy c o n d u i t
700.00'
Equipment I n s t a l l a t i o n
2,600.00
5 Man-weeks engineering t i m e
6,000.00
$ 20,316.50
Approximately 8100 f e e t
D i r e c t b u r i a l cable
@$3.00/foot
$ 24,300.00
Jack & Bore under ramps
Approx. 200 f e e t @$20./foot
4,000.00
Conduit over r i v e r &
intersections
Approx. 1300
feet @$6. / f o o t
7,800.00
5 l an-wee~s engineering t i m e
6 yOOO.OO
.
1
1
$ 42,100.00
I
Section 10
Conclusions and Recommendations
CONCLUSIONS AND RECOMMENDATIONS
The RF system, as s t u d i e d i n F o r t Worth, performed as an a l t e r n a t i v e
t o a d i r e c t w i r e l i n e i n t e r c o n n e c t between e n t r a n c e ramp c o n t r o l l e r s .
RF system performed as a one-way com~nunications l i n k .
The
While t h e s h o r t and
e x t e n s i v e s t u d y d i d n o t d i s c o v e r any m a j o r m a l f u n c t i o n s o r e r r o r s due t o
i n t e r f e r e n c e o r equipment m a l f u n c t i o n s , t h e t o t a l o p e r a t i o n a l p i c t u r e f o r
t h i s equipment has n o t been determined.
Based on experiences i n o t h e r
i n d u s t r i e s u s i n g t h i s equipment, one o r two s e r v i c e c a l l s p e r y e a r a r e
t o be expected.
As t h e SDHPT g a i n s more experience t h r o u g h t h e use of t h i s
RF equipment, a more thorough understanding o f t h e o p e r a t i o n a l and niaintenance requirements w i 1 1 be achieved
.
One area t h a t needs s t a n d a r d i z a t i o n i s t h e s e l e c t i o n o f t h e RF frequency.
The FCC has a l l o c a t e d s e v e r a l frequency bands s p e c i f i c a l l y f o r S t a t e Highway
agencies t o be used f o r d a t a communications.
The SDHPT can u t i l i z e t h e i r
e x p e r t i s e i n s e l e c t i n g s e v e r a l f r e q u e n c i e s which can be used t h r o u g h o u t t h e
state.
More t h a n one frequency c o u l d be needed i n t h e e v e n t n e i g h b o r i n g
c i t i e s ( f o r example F o r t Worth and D a l l a s ) operates s e v e r a l groups o f RF
i n t e r c o n n e c t i n g ramps.
By s e l e c t i n g d i f f e r e n t f r e q u e n c i e s f o r each c i t y ,
i n t e r f e r e n c e between c i t i e s w i l l be e l i m i n a t e d .
frequency can be used.
W i t h i n a c i t y , t h e same RF
Each ramp i n t e r c o n n e c t group ( a t r a n s m i t t e r and
s e v e r a l r e c e i v e r s ) can be g i v e n a u n i q u e s t a t i o n address.
The r e c e i v e r s w i l l
o n l y respond t o t h e RF s i g n a l h a v i n g t h e unique s t a t i o n address.
Messages
from a l l o t h e r t r a n s m i t t e r s on t h e same channel w i t h d i f f e r e n t addresses
w i l l be d i s r e g a r d e d .
The RF equipment, as u t i l i z e d i n t h e study, i s c u r r e n t l y i n p r o d u c t i o n
and c o n t a i n s no u n i q u e components o r c i r c u i t s s p e c i f i c a l l y i n s t a l l e d f o r t h e
SDHPT's use.
Therefore, t h e RF equipment can be u t i l i z e d as shipped f r o m t h e
factory.
t h e SDHPT.
A1 1 i n s t a l 1a t i o n e x p e r t i s e needed i s p r e s e n t l y a v a i l a b l e w i t h i n
The RF equipment can be used as a c o s t e f f e c t i v e a l t e r n a t i v e
t o a d i r e c t w i r e 1 i n e ramp c o n t r o l i n t e r c o n n e c t .
REFERENCE
1.
Van Cott, H.P. and Kinkade, R.G.,
"Human Engineering Guide t o Equipment
Design," American I n s t i t u t e o f Research, Washington, D.C.,
1972.
Append i c e s
APPENDIX A.
INTRODUCTION
T h e T r a n s - T r o n i c s Rarnp M e t e r i n g C o n t r o l 1 e r was d e s i g n e d t o
c o n t r o l v e h i c l e access t o a freeway i n r e l a t i o n t o t h e
I t i s a m i c r o p r o c e s s o r based
l e v e l o f freeway occupancy.
d i y i t a l c o n ~ p u t e ru s i n g t h e l a t e s t s t a t e o f t h e a r t L S I
p r o c e s s i r l g c o r ; ~ p o n e r l t s i n c o n j u n c t i o n w i t h 1 ow p o w e r / h i g h
n o i s e i m m u n i t y CMOS i n t e g r a t e d c i r c u i t s .
The c o n t r o l l e r
i s o f m o d u l a r d e s i g n u s i n g 1004, s o l i d s t a t e c o c l p o n e n t s a n d
w i l l o p e r a t e o v e r a t e r l ~ p e r a t u r e r a n g e o f - 3 0 ° F t o +165OF.
A l l t i w i n g i s d i g i t a l a n d r e f e r e n c e d t o t t l e 6 0 Hz l i r l e
frequency.
C o r ~ t r o lel r p r o g r a m m i n g i s p e r f o r m e d q u i c k l y
a.nd e a s i l y b y i n s e r t i n g p r o y r a l l l p i n s i n t o s l o t s o n t h e
The c o n t r o l l e r i s f u l l y
f r o n t o f t h e CPU m o d u l e .
r e s p o n s i v e t o systems d e t e c t o r i n p u t s and c a n o p e r a t e
s t a n d - a 1 o n e o r as a ~ a a s t e r / s e c o n d a r y i n a n i n t e r c o n n e c t e d
systern.
T h e c o n t r o l l e r may a l s o b e i n t e r f a c e d w i t h a n d
s u p e r v i s e d b y a r e r ~ ~ o t e ll yo c a t e d m a s t e r c o n ~ p u t e r .
A t y p i c a l ramp n e t e r i n y c o n t r o l l e r i n s t a l l a t i o n i s shown
b e 1 ow:
DETECTOR LOCATIONS
CONTROLLER
Q
Q
QUEUE
0
Q
FLASHER
-
FREEWAY
------------
GENERAL UESCRIPTION
Introduction
T h e c o r ~ t r o lel r [nay b e p r o g r a ~ , ~ r n etdo o p e r a t e s e v e r a l
d i f f e r e n t ways.
It i s capable o f being e i t h e r f u l l y
t r a f f i c responsive, enabled by a ticie clock, remotely
c o n t r o l l e d b y a corrlputer, o r any c o r n b i n a t i o n o f t h e above.
E a c h rliodc o f opera ti or^ w i l l b e d e s c r i b e d i n t h i s s e c t i o n .
Actuated Operat i o n
Basic Operation (Segr~ienter)
The c o n t r o l 1e r c o n t i n u o u s l y rheasures t h e p e r c e n t a g e o f
f r e e w a y 1ane occupancy o v e r d programmable i n t e r v a l frorn
1 3 2 r l l i n u t e t o 7 r i ~ i n u t e s . Eased on t h e f r e e w a y o c c u p a n c y
w i l l be
p e r c e n t a g e , one o f f i v e segments (A t h r u E )
s e l e c t e d f ror:i p r o g r a l ~ i r i ~ e sde g m e n t p e r c e n t 1 e v e l s.
The
c o n t r o l l e r w i l l s e l e c t t h e h i g h e s t seynent w i t h i n a
p r o y r r i i n ~ e d 1 e v e l , n o t e x c e e d i 119 t h e m e a s u r e d f r e e w a y
occupancy percentage.
Once a s e y n e n t l e v e l o f B o r
g r e a t e r has been s e l e c t e d , t h e c o n t r o l l e r w i l l n o t r e t u r n
t o l e v e l A u n t i l t h e freeway occupancy percentage l ~ a s
f a 1 l e n b e l o w t h e l e v e l p r o g r a m m e d f o r s e g m e n t A.
When a stlgrilent l e v e l o f B o r g r e a t e r i s c a l l e d f o r , t h e
c o n t r o l l e r w i l l i n i t i a t e ramp m e t e r i ng o p e r a t i o n .
A t the
s t a r t o f ~ ~ l e t e r i nogp e r a t i o n , a t w o c i r c u i t f l a s h i n g b e a c o n
s i y n a l w i l l be e n e r g i z e d and r e m a i n on f o r t h e d u r a t i o n of
metering operation.
M e t e r i n g w i 1 1 in i J i a t e w i t h a g r e e n
s i g n a l o f 15 seconds, f o l l o w e d by a y e l l o w s i g n a l f o r 3
seconds, and t h e n r e s t i n r e d .
The d u r a t i o n o f t h e r e d s i g n a l i n t e r v a l i s d e t e r m i n e d b y
t h e proyrrnnied m e t e r i n y r a t e f o r t h e s e l e c t e d segment ( B
thru E).
A f t e r t h e r e d m e t e r i n y i n t e r v a l has tiriled o u t ,
t h e c o n t r o l l e r w i l l r e s p o n d t o demand c o n d i t i o n s .
The
s u D s e q u e n t g r e e n a n d y e l l o w i n t e r v a l t i m e s w i l l be as
progranllned.
Demand C o n d i t i o n s
Following t h e red tiriiiny i n t e r v a l , t h e c o n t r o l l e r w i l l
e n t e r a r e a d y s t a t e f o r a dell!a~id c a l l .
When a demand i s
p r e s e n t , t h e g r e e n i n t e r v a l w i l l be s t a r t e d p r o v i d e d t h e r e
Should a
i s no v e h i c l e p r e s e n t on t h e merge d e t e c t o r .
v e h i c l e be p r e s e n t on t h e merye d e t e c t o r , t h e c o n t r o l l e r
w i l l reudin i n a red state u n t i l e i t h e r the vellicle leaves
t h e l n e r y e d e t e c t o r o r t h e riierge i n t e r v a l t i r ~ ~ eh ar s t i m e d
o u t , a t w h i c h t i m e t h e v e h i c l e o n t h e deri~arid d e t e c t o r w i l l
be s e r v i c e d .
A c?ertland c a l 1 w i l l b e r e g i s t e r e d i n t h e c o n t r o l l e r IJeriiory
f o r dny o f t l i e f o l l o w i n g c o n d i t i o r i s :
1. A v e h i c l e i s p r e s e n t o n t i l e demand d e t e c t o r .
2.
A v e h i c l e i s p r e s e n t on t h e queue d e t e c t o r and t h e
p r o g r a m r i l e d q u e u e i n t e r v a l tias t i m e d o u t .
3.
There have been f i v e a c t u a t i o n s o f t h e merge
d e t e c t o r w i t h o u t a n a c t u a t i o n o f t h e demand
detector.
T h i s s i t u a t i o n i s d e f i n e d a s a demand
d e t e c t o r f a i l u r e and w i l l r e m a i n u n t i l t h e r e i s
e i t h e r a n a c t u a t i o n o f t h e dertiarid d e t e c t o r o r t l i e
control l e r i s reset.
S e l e c t a b l e Modes o f O p e r a t i o n
T h e c o n t r o l l e r rilay b e p r o g r a n i m e d t o o p e r a t e i n o n e o f t h e
f o l l o w i n g f o u r niodes u s i n g c o ~ ~ i b i n ccdo n d i t i o n s o f t h e
s e g r ~ e n t e r a n d t h e t i r ~ i ec l o c k :
1. CLOCK: When t h e c l o c k i n p u t i s o f f , t h e s e g m e n t e r
o u t p u t i s f o r c e d t o l e v e l A.
When t l i e c l o c k i n p u t
i s on, t h e l e v e l i s t h e s t y r i ~ e n t e r l e v e l o u t p u t based
on freeway occupancy.
2.
CLOCK + NOT LEVEL A : When t h e c l o c k i n p u t i s o f f ,
the segnenter output i s forced t o l e v e l A.
When t h e
c l o c k i n p u t i s or], t h e l e v e l i s f o r c e d t o B o r t h e
segr;ienter o u t p u t , w h i c h e v e r i s g r e a t e r .
3.
SECMENTER: When t l i e s e g l l i e n t e r l e v e l i s g r e a t e r t h e 1 1
A, ramp m e t e r i n g w i l l o c c u r .
4.
SEGKENTER + CLOCK: When t h e c l o c k i n p u t i s o f f ,
tlie
l e v e l i s t h e seyriienter o u t p u t .
When t l i e c l o c k i n p u t
i s on, t h e l e v e l i s f o r c e d t o B o r t h e s e g m e n t e r
output, which ever i s greater.
O n c e t h e seyn:ent l e v e l i s d e t e r m i n e d f o r t h e p r o g r a ~ ; ~ m e d
rrlode o f o p e r a t i o n , t h e r e m o t e c o r r ~ p u t e r l e v e l i n p u t i s
examined and t h e c o n t r o l l e r s t a t e w i l l be s e t t o t h e
greater of t h e two levels.
I f t h e ONLItIE CONTROL i n p u t i s
t r u e , t h e c o n t r o l l e r s t a t e w i l l be s e t t o t h e r e m o t e
c o ~ ; ~ p u t el re v e l .
Oriline Control w i l 1 a l s o f o r c e a freeway
averaging period o f 1/2 minute.
N o n - A c t u a t e d O p e r a t i on
P r o v i s i o r i s a r e rnade f o r c o n t r o l o f t h e r a m p s i g n a l u s i n g a
rnanual p u s h b u t t o n .
When t h e p u s h b u t t o n c a b l e j a c k i s
c o n n e c t e d , t h e c o n t r o l l e r g o e s i n t o rnanual n o d e a t t h e r e d
condition.
A c t i v a t i o n o f t h e push b u t t o n w i l l advance t h e
s i g n a l one i n t e r v a l .
Removal o f t h e j a c k o r r e t u r n i n y manual s w i t c h back t o
a u t o w i l l r e t u r n t h e c o n t r o l l e r t o t h e a u t o m a t i c mode o f
operation.
By-Pass S e r v i c e
I n t e r f a c e s i g n a l s f o r t h e a d d i t i o n o f a by-pass c o n t r o l
module have been d e f i n e d f o r f u t u r e expansion.
(See
section 7).
Re-Start
The ramp m e t e r i n g c o n t r o l l e r has been d e s i g n e d
~ i o r n i a l o p e r a t i o n f o r a l o s s o f AC l i n e v o l t a g e
second d u r a t i o n .
R e - s t a r t from a power l o s s o
t h a n 1/2 second w i l l o c c u r w i t h a l l c o n d i t i o n s
t o continue
up t o 1/2
f greater
reset.
A v o l t a y e n o n i t o r c i r c u i t w i t h i n ttie c o n t r o l l c r w i l l h a l t
o p e r a t i o 1 1 \:llcrl t h e A C 1 i r l e v o l t a y e f a 1 1 s o u l o w 3 0 V A L .
A e i a t c l ~ d o ? ;t i m e r c i r c u i t w i l l r e s e t t h e c o r ~ t r o l l e r i f a
f a u l t occurs i n tire normal sequence o f proyranl e x e c u t i o n .
TECHNICAL DATA
Introduction
The ramp n r e t e r i n g c o n t r o l l e r i s a m i c r v p r o c e s s o r based
d i y i t a l c o m p u t e r u s i n y 1 ow p o w e r TTL p r o c e s s i r ~ g c o m p o n e n t s
arid l l i y l i n o i s e i m m u n i t y C M O S i n p u t l o u t p u t c o m p o n e n t s .
These d e v i c e s a r e c o n f i y u r e d i n t h r e e removable p r i n t e d
c i r c u i t b o a r d modules w h i c h c o n n e c t t o a comclon
i i ~ o t t ~ e r b o a r d .A s p a r e s l o t on t h e m o t h e r b o a r d i s p r o v i d e d
f o r f u t u r e e x p a n s i o n and i s c o v e r e d w i t h a b l a n k p a n e l
d u r i n y norrr~al o p e r a t i o n .
CPU F i o d u l e
T h e CPU r r l o d u l e c o r l t a i n s a l l t h e c o m p o n e n t s a n d c i r c u i t r y
TTL
necessary t o perforrn t h e c o n t r o l l e r l o g i c f u n c t i o n s ,
The
t o CMOS b u f f e r i n g and p r o g r a m p a n e l i n p u t s .
m i c r o p r o c e s s o r c h i p o b t a i n s i n s t r u c t i o n s from 1 0 2 4 b y
8 - b i t b y t e s o f p r o g r a ~ ~ ~ r t rea br le a d - o n l y iilernory ( PROtl)
I n f ~ r r ~ l a t i oi ns b r o u g h t i n t h r o u g l i i n p u t b u f f e r s , s t o r e d
and ~ : i a n i p u l a t e di n 1 2 8 b y 8 - b i t b y t e s o f r a n d o m - a c c e s s
1ner;lory ( R A M ) , a n d t h e n s e n t o u t t h r o u g h o u t p u t b u f f e r s .
T i m i n g a c c u r a c i e s a r e m a i n t a i n e d b y u s i n y t h e 6 0 tiz p o w e r
1 i n e frequency as a r e f e r e n c e .
.
T h e 110 r D i o d u l e c o n t a i n s t h e i n t e r f a c e t o e x t e r n a l c o n t r o l
signals.
P r o v i s i o n s a r e r~ladef o r 1 6 o p t i c a l l y - i s o l a t e d
i n p u t s a t ~ d3 2 l a t c h e d t r a n s i s t o r - b u f f e y e d o u t p u t s .
D i s p l a y / P o w e r S u p p l y I . ? o d u le
CPU c o r l t r o l f u n c t i o n s and s t a t u s i n d i c a t o r s a r e c o n t a i n e d
on t h e d i s p l a y module.
T h e d i s p l a y l i y t ~ t smay b e d i s a b l e d
d u r i n g unattended o p e r a t i o n t o conserve power and p r o l o n g
1ar11p l i f e .
e and
DC v o l t a g e s a r e g e n e r a t e d o n t h e p o w e r s u p p l y 111odu1
~ ~ i o n i t o r ef do r a b r o w n - o u t c o n d i t i o n s h o u l d t h e A C l i n e
v o l t a g e f a l l below t h e s p e c i f i e d o p e r a t i n g ranye.
The
w a t c h d o g t i m e r c o n t i n o u s l y ~ i ~ ot no ir s t h e c o n t r o l 1 e r f o r
proper operation.
An i n v a l i d p r o g r a m s e q u e n c e w i l l
generate a c o n t r o l l e r reset t o r e s t o r e proper operation.
CONTROLLER OPERATION
Introduction
The ramp m e t e r i n g c o n t r o l l e r i s d e s i g n e d t o c o n t r o l
v e t ~ i c l ea c c e s s t o f r e e w a y t r a f f i c i n r e s p o n s e t o t h e
A c c e s s i s c o n t r o l 1ed b y 1 i m i t i n g
f r e e w a y o c c u p a n c y 1e v e l .
the r a t e a t which vehicles are allowed t o enter the
freeway using a three-sect i o n signal (red, ye1low, green).
V e l i i c u l a r t r a f f i c i n f o r ~ n a t i o ni s s e n t t o t h e c o n t r o l l e r
from f o u r d e t e c t o r inputs.
One d e t e c t o r r e s p o n d s t o t h e
presence o f v e h i c l e s on t h e freeway t o determine t h e
p e r c e n t a g e o f o c c u p a n c y d u r i r ~ ya p r o g r a m r r i a b l e p e r i o d o f
1.12 m i n u t e t o 7 m i n u t e s .
The r e m a i n i n g t h r e e d e t e c t o r s
sense v e t i i c l e s a t d i f f e r e n t l o c a t i o n s on t h e e n t r a n c e
rarilp.
T h e deliland d e t e c t o r i s l o c a t e d t o s e n s e v e h i c l e s a t
t h e s t o p l i n e o f t h e rarnp c o n t r o l s i g n a l .
The merge
d e t e c t o r i s l o c a t e d downstream from t h e s t o p l i n e t o sense
v e h i c l e s j u s t p r i o r t o e n t e r i n g t h e freeway.
The queue
d e t e c t o r i s l o c a t e d upstream of t h e s t o p l i n e , a t l o r near
t h e i n t e r s e c t i o n o f t h e e n t r a n c e ramp and t h e f r o n t a g e
road.
There a r e f i v e programmable l e v e l s o f freeway occupancy
During
percentage, i d e n t i f i e d as l e v e l A t h r o u g h l e v e l E.
l e v e l A, t h e c o n t r o l l e r i s n o t m e t e r i n g r a m p t r a f f i c a n d
the signal i s off.
I n l e v e l B o r a b o v e , rarlip t r a f f i c i s
m e t e r e d and t h e s i y n a l i s o p e r a t i n g .
If the coritroller i s
i n l e v e l A, t h e o c c u p a n c y p e r c e n t a g e m u s t e q u a l o r e x c e e d
If the controller i s atlor
bevel B t o i n i t i a t e operation.
b e l o w l e v e l B, t h e c o n t r o l l e r w i l l n o t c e a s e t o m e t e r
t r a f f i c u n t i l ttie occupancy percentage- f a l l s below t h e
v a l u e s e t f o r l e v e l A.
i s
F o r each o p e r a t i n g segrnenter l e v e l B t h r o u g h E, t h e r e
a n a s s o c i a t e d progralrlrilable m e t e r i n g r a t e B t h r o u g h E , i n
t h e r a n g e o f 112 t o 63 112 seconds o f r e d p e r v e h i c l e .
I n a d d i t i o n t o s i g n a l head c o n t r o l o u t p u t s , t h e c o n t r o l l e r
w i l l o u t p u t s t a t u s inforriiation f o r a remote computer.
T h i s i n f o r ~ ~ a t i oc no n s i s t s o f b i n a r y d a t a a s f o l l o w s :
1. S e g r i i e n t L e v e l
2. Freeway Occupancy
3.
4.
5.
Freeway Volume
Detector Status
Greet1 C o n f i r m
(3-bits)
(7-bits)
(7-bits)
(4-bits)
(1-bit)
Occupancy i s u p d a t e d once each f r e e w a y a v e r a g i ny i n t e r v a l
and volurire i s u p d a t e d orice e a c h 3 0 s e c o n d s .
APPENDIX B.
PART 90
--
FCC REGULATIONS
PRIVATE LAND MOBILE RADIO SERVICES
Subpart B - P u b l i c S a f e t y Radio S e r v i c e s
90.15
Scope.
90.17
Local government r a d i o s e r v i c e .
90.19
Pol i c e Radio S e r v i c e .
90.21
F i l e Radio S e r v i c e .
90.23
Highway Maintenance Radio S e r v i c e .
90.25
F o r e s t r y - C o n s e r v a t i o n Radio S e r v i c e .
Subpart A
3
90.1
-
General I n f o r m a t i o n
B a s i s and purpose.
(a)
The r u l e s i n t h i s p a r t a r e promulgated under T i t l e I 1 o f t h e Comnunications A c t o f 1934, as amended
Basis.
which v e s t s a u t h o r i t y i n t h e Federal Comnunications Comnission t o r e g u l a t e r a d i o t r a n s m i s s i o n and t o i s s u e l i c e n s e s f o r
radio stations.
A l l r u l e s i n t h i s p a r t a r e i n accordance w i t h a p p l i c a b l e t r e a t i e s and agreements t o which t h e U n i t e d
States i s a party.
( b ) Purpose. T h i s p a r t s t a t e s t h e c o n d i t i o n s under w h i c h r a d i o communications systems may be l i c e n s e d and used
i n t h e P u b l i c S a f e t y , S p e c i a l Emergency, I n d u s t r i a l , Land T r a n s p o r t a t i o n , and R a d i o l o c a t i o n Radio S e r v i c e s . These
r u l e s do n o t govern r a d i o systems employed by agencies o f t h e Federal Government.
1 90.3
O r g a n i z a t i o n and a p p l i c a b i l i t y o f t h e r u l e s .
The r u l e s i n t h i s p a r t a r e d i v i d e d i n 17 s u b p a r t s as f o l l o w s :
( a ) Subpart A c o n t a i n s g e n e r a l i n f o r m a t i o n and d e f i n i t i o n s f o r use i n t h i s p a r t .
( b ) Subparts B, C, D, E, and F s e t f o r t h t h e r a d i o s e r v i c e s governed under t h i s p a r t and i n c l u d e e l i g i b i l i t y
p r o v i s i o n s , l i s t i n g o f f r e q u e n c i e s a v a i l a b l e f o r each r a d i o s e r v i c e , and s p e c i a l r e q u i r e m e n t s and l i m i t a t i o n s a p p l i c a b l e
t o a p a r t i c u l a r radio service.
( c ) Subpart G d e s c r i b e s t h e procedures and r e q u i r e m e n t s f o r f i l i n g a p p l i c a t i o n s and l i c e n s i n g r a d i o s t a t i o n s under
t h i s part.
( d ) Subpart H p r o v i d e s r e q u i r e m e n t s f o r s e l e c t i o n o f f r e q u e n c i e s .
( e ) Subpart I c o n t a i n s general t e c h n i c a l s t a n d a r d s f o r use o f equipment under t h i s p a r t .
( f ) Subpart J c o n t a i n s s t a n d a r d s f o r c e r t a i n s p e c i a l i z e d uses.
( g ) Subpart K c o n t a i n s s t a n d a r d s f o r t h e use o f c e r t a i n f r e q u e n c i e s o r f r e q u e n c y bands.
( h ) Subpart L c o n t a i n s s p e c i a l r e g u l a t i o n s f o r o p e r a t i o n i n t h e 470-512 MHz band.
( i ) Subpart M c o n t a i n s s p e c i a l r e g u l a t i o n s f o r o p e r a t i o n s i n t h e 806-821 and 851-866 MHz bands.
( j ) Subpart N s e t s f o r t h system o p e r a t i n g r e q u i r e m e n t s .
( k ) Subpart 0 c o n t a i n s s p e c i a l r e g u l a t i o n s f o r o p e r a t i o n i n t h e Chicago Land M o b i l e Spectrum Management D i s t r i c t .
( 1 ) Subpart P c o n t a i n s r e g u l a t i o n s f o r t h e a u t h o r i z a t i o n o f developmental o p e r a t i o n s .
(m) Subpart Q c o n t a i n s r e g u l a t i o n s f o r emergency o p e r a t i o n s i n t h e I n d u s t r i a l Radio S e r v i c e s (ICEP), and i n t h e
Land T r a n s p o r t a t i o n Radio S e r v i c e s (LATICEP).
Subpart B
8
90.15
-
P u b l i c S a f e t y Radio S e r v i c e s
Scope.
The P u b l i c S a f e t y Radio S e r v i c e s i n c l u d e t h e Local Government, P o l i c e , F i r e , Highway Maintenance and F o r e s t r y C o n s e r v a t i o n Radio S e r v i c e s .
Rules as t o e l i g i b i l i t y f o r 1 i c e n s i n g , f r e q u e n c i e s a v a i l a b l e , and any s p e c i a l r e q u i r e -
ments as t o each o f t h e s e r a d i o s e r v i c e s a r e s e t f o r t h i n t h e f o l l o w i n g s e c t i o o s .
8
90.23
Highway Maintenance Radio Service
.
.
Any t e r r i t o r y . possession. State. county. c i t y . town. and s i m i l a r governmental e n t i t y i s
(a) E l i g i b i l i t y
e l i g i b l e t o hold a u t h o r i z a t i o n s i n t h e Highway Maintenance Radio S e r v i c e t o operate s t a t i o n s f o r t.ransmission
of comnunications e s s e n t i a l t o o f f i c i a l highway a c t i v i t i e s o f t h e l i c e n s e e
.
.
The f o l l o w i n g t a b l e i n d i c a t e s frequencies a v a i l a b l e f o r assignment t o s t a t i o n s i n
( b ) Frequencies a v a i l a b l e
the Highway Maintenance Radio Service. t o g e t h e r w i t h t h e c l a s s o f s t a t i o n ( s ) t o which t h e y a r e normally assigned and
t h e s p e c i f i c . assignment l i m i t a t i o n s which a r e explained i n paragraph ( c ) o f t h i s s e c t i o n :
Highway Maintenance Radio Service Frequency Table
Frequency
o r band
Class o f s t a t i o n ( s )
Limitations
Frequency
o r band
Class o f s t a t i o n ( s )
Megahertz:
.....
.............
.............
Base o r m o b i l e
do
.... do .............
do
do
do
....do
Base o r mobile .....
.... do
....do
....do .............
....do .............
do
....do
do
do .............
.do
....do
....
....
....
....
.............
.............
.............
.............
.............
.... .............
.............
.... .............
....
... .............
.............
....uu.............
....do .............
....do .............
. . . . A n .............
....do .............
....do .............
....do .............
....do .............
....do .............
....do .............
... .do .............
. . . . do .............
....do .............
....do .............
....do .............
Operational f i x e d ..
Base o r mobile .....
do .............
....do .............
....do
....do .............
....do .............
do
....do
do
do
Mobile
do
do .............
Base o r mobile
do
do
do .............
do
do .............
do .............
....do .............
do
do .............
do
....
.............
....
....
....
.............
.............
.............
.............
.............
.... .............
....
.....
.... .............
.... .............
....
.... ............
....
....
.... .............
....
.... .............
..........
..........
..........
..........
..........
..........
..........
..........
..........
....do .............
....do .............
....do .............
....do .............
....do .............
Base o r mobile .....
....do .............
....do .............
....do .............
....do .............
....do .............
Fixed ..............
Base o r mobile .....
....do .............
. . . .do .............
....do .............
....do .............
Base o r m o b i l e .....
....do .............
....do .............
....do .............
....do .............
....do .............
....do .............
....do .............
....do .............
....do .............
....do ....,........
....do .............
....do .............
....do .............
Mobile .............
....do .............
....do .............
....do .............
....do .............
....do .............
....do .............
....do .............
....do .............
....do .............
.... do .............
....do .............
....do .............
....do .............
....do .............
....do .............
....do .............
....do .............
....do .............
Base o r mobile .....
Mobile .............
Base o r m o b i l e .....
Operational f i x e d ..
453.350
453.400
453.450
453.500
453.550 ..........
453.600
453.650
453.700
453.750
453.800
453.850
453.900 ..........
453.950 ..........
458.050 ..........
458.100
458.150 ..........
458.200 ..........
458.250
458.300 ..........
458.350 ..........
458.400
458.450
458.500.
458.550
458.600
458.650
458.700
458.750
458.800
458.850
458 .900
458.950
470-512
806-821
851-866
952 and above
1427-1435 ........ Operational f i x e d ,
base o r mobile ...
Base o r mobile
do
..........
..........
..........
..........
..........
.........
..........
..........
..........
..........
....:.....
..........
..........
..........
..........
..........
..........
..........
....
.....
.... .............
Limitations
(c)
E x p l a n a t i o n o f assignment l i m i t a t i o n s a p p e a r i n g i n t h e f r e q u e n c y t a b l e o f p a r a g r a p h ( b ) o f t h i s s e c t i o n :
(1)
T h i s f r e q u e n c y i s shared w i t h t n e S p e c i a l Emergency Radio S e r v i c e .
( 2 ) T h i s f r e q u e n c y w i l l be a s s i g n e d o n l y i n accordance w i t h a g e o g r a p h i c a l assignment p l a n and i s r e s e r v e d
p r i m a r i l y f o r assignment t o Highway Maintenance systems o p e r a t e d by s t a t e s . The use o f t h i s f r e q u e n c y by o t h e r
Highway maintenance l i c e n s e e s w i l l be a u t h o r i z e d o n l y where such use i s n e c e s s a r y t o c o o r d i n a t e a c t i v i t i e s w i t h
t h e p a r t i c u l a r s t a t e t o which t h e frequency i s assigned.
Any r e q u e s t f o r such use must be s u p p o r t e d by a s t a t e -
ment f r o m t h e s t a t e concerned.
(3)
5
The f r e q u e n c i e s a v a i l a b l e f o r use a t o p e r a t i o n a l f i x e d s t a t i o n s i n t h e band 72-76 MHz a r e l i s t e d i n
90.257(a)(l).
provisions o f
(4)
These f r e q u e n c i e s a r e shared w i h t o t h e r s e r v i c e s and a r e a v a i l a b l e o n l y i n accordance w i t h t h e
8
90.257.
T h i s f r e q u e n c y i s n o t a v a i l a b l e f o r assignment t o s t a t i o n s i n t h e Highway Maintenance Radio S e r v i c e
l o c a t e d i n P u e r t o R i c o and t h e V i r g i n I s l a n d s .
( 5 ) T h i s frequency i s r e s e r v e d f o r assignment f o r use i n highway maintenance systems o p e r a t e d by l i c e n s e s
o t h e r than States.
(6)
1952.
T h i s f r e q u e n c y i s o n l y a s s i g n e d t o Highway Maintenance s t a t i o n s l i c e n s e d f o r i t s use p r i o r t o A p r i l 28,
Such use may c o n t i n u e on a secondary b a s i s t o any government o r non-government r a d i o o p e r a t i o n
( 7 ) The f r e q u e n c i e s a v a i l a b l e f o r use a t f i x e d s t a t i o n s i n t h i s band, and t h e r e q u i r e m e n t s f o r assignment
a r e s e t f o r t h i n 5 90.261.
O p e r a t i o n on t h e s e f r e q u e n c i e s i s secondary t o s t a t i o n s i n t h e I n d u s t r i a l and Land
T r a n s p o r t a t i o n Radio S e r v i c e s where t h e y a r e a s s i g n e d f o r l a n d m o b i l e o p e r a t i o n s .
(8)
T h i s f r e q u e n c y i s a v a i l a b l e i n t h i s s e r v i c e on a shared b a s i s w i t h a l l o t h e r P u b l i c - S a f e t y Radio S e r v i c e s .
(9)
Subpart L c o n t a i n s r u l e s f o r assignment o f f r e q u e n c i e s i n t h e 470-512 MHz band.
( 1 0 ) Subpart M c o n t a i n s r u l e s f o r assignment o f f r e q u e n c i e s i n t h e 806-821 and 851-886 MHz bands.
( 1 1 ) Assignment o f f r e q u e o c i e s f o r o p e r a t i o n a l - f i x e d s t a t i o n s i n t h e bands 952 and above i s governed by P a r t
94 o f t h i s Chapter.
( 1 2 ) T h i s f r e q u e n c y band i s a v a i l a b l e t o s t a t i o n s i n t h i s s e r v i c e s u b j e c t t o t h e p r o v i s i o n s o f
5
90.259.
( 1 3 ) A v a i l a b l e o n l y on a shared b a s i s w i t h s t a t i o n s i n o t h e r s e r v i c e s , and s u b j e c t t o no p r o t e c t i o n f r o m
i n t e r f e r e n c e due t o t h e o p e r a t i o n o f i n d u s t r i a l , s c i e n t i f i c , o r medical (ISM) d e v i c e s .
( 1 4 ) T h i s f r e q u e n c y may n o t be a s s i g n e d w i t h 100 m i l e s o f New Orleans ( c o o r d i n a t e s 29-56-53 N and 90-04-10 W ) .
(d)
Additional frequencies available.
I n a d d i t i o n t o t h e f r e q u e n c i e s shown i n t h e f r e q u e n c y t a b l e o f t h i s
section, the following frequencies are available i n t h i s service.
(1)
The f r e q u e n c i e s 27.235,
27.245, 27.255, 27.265,
(See a l s o
8
90.253.)
dnd 27.275 MHz a r e a v a i l a b l e i n accordance w i t h
5
90.255.
( 2 ) The f r e q u e n c y bands 31.99 t o 32.00 MHz, 33.00 t o 33.01 MHz, 33.99 t o 34.00 MHz, 37.93 t o 38.00 MHz,
39.00 t o 39.01 MHz, 39.99 t o 40.00 MHz and 42.00 t o 42.01 MHz a r e a v a i l a b l e f o r assignment f o r developmental
o p e r a t i o n , s u b j e c t t o t h e p r o v i s i o n s o f Subpart P.
( 3 ) Frequencies i n t h e band 73.0-74.6 MHz may be a s s i g n e d t o s t a t i o n s a u t h o r i z e d t h e i r use on o r b e f o r e
December 1, 1981, b u t no new s t a t i o n s w i l l be a u t h o r i z e d i n t h i s band, n o r w i l l expansion o f e x i s t i n g systems be
p e r m i t t e d . (See a l s o
5
90.257.)
N o r m a l l y o n l y two f r e q u e n c i e s o r p a i r s of f r e q u e n c i e s
( e ) L i m i t a t i o n on number o f f r e q u e n c i e s a s s i g n a b l e .
i n t h e p a i r e d f r e q u e n c y mode o f o p e r a t i o n , w i l l be assigned f o r m o b i l e s e r v i c e o p e r a t i o n s by a s i n g l e a p p l i c a n t
i n a g i v e n area.
The assignment o f an a d d i t i o n a l f r e q u e n c y o r p a i r o f f r e q u e n c i e s w i l l be made o n l y upon a
s a t i s f a c t o r y showing o f need, e x c e p t t h a t :
( 1 ) A d d i t i o n a l f r e q u e n c i e s above 25 MHz may be a s s i g n e d i n c o n n e c t i o n w i t h t h e o p e r a t i o n o f m o b i l e r e p e a t e r s
i n accordance w i t h f 90.247, n o t w i t h s t a n d i n g t h i s 1 i m i t a t i o n .
( 2 ) Frequencies i n t h e 25-50 MHz, 150-170 MHz and 450-512 MHZ bands, and t h e f r e q u e n c y bands 903-904 MHz,
904-912 MHz, 918-926 MHz and 926-927 MHz may be a s s i g n e d f o r t h e o p e r a t i o n o f A u t o m a t i c V e h i c l e M o n i t o r i n g (AVM)
systems i n accordance w i t h
f
90.239,
notwithstanding t h i s l i m i t a t i o n .
Subpart H - P o l i c i e s Governing t h e Assignment o f Frequencies
f
90.171
Scope.
T h i s s u b p a r t c o n t a i n s d e t a i l e d i n f o r m a t i o n c o n c e r n i n g t h e p o l i c i e s under w h i c h t h e Conunission a s s i g n s f r e q u e n c i e s
f o r t h e use o f l i c e n s e s under t h i s p a r t , f r e q u e n c y c o o r d i n a t i o n procedures, and procedures under which l i c e n s e e s
may c o o p e r a t i v e l y s h a r e r a d i o f a c i l i t i e s .
5
90.173
P o l i c i e s g o v e r n i n g t h e assignment o f f r e q u e n c i e s .
..........................................................
( f ) I n t h e 150-170 MHz band, no a p p l i c a t i o n w i l l be g r a n t e d which proposes a base s t a t i o n l o c a t e d l e s s t h a n
16 km ( 1 0 m i . ) from an e x i s t i n g base s t a t i o n on a frequency 15 kHz removed.
I n t h e Taxicab Radio S e r v i c e , t h e
minimum s e p a r a t i o n i s 12 km ( 7 m i . ) .
Subpart J - Non-Voice and Other S p e c i a l i z e d Operations
5 90.231
Scope.
T h i s s u b p a r t s e t s f o r t h requirements and standards f o r l i c e n s i n g and o p e r a t i o n o f non-voice and o t h e r s p e c i a l i z e d r a d i o used ( o t h e r t h a n r a d i o l o c a t i o n ) .
Such uses i n c l u d e secondary s i g n a l i n g , t e l e m e t r y , r a d i o t e l e p r i n t e r .
r a d i o f a c s i m i l e , automatic v e h i c l e m o n i t o r i n g (AVM), r a d i o c a l l box, r e l a y , v e h i c u l a r r e p e a t e r , and c o n t r o l s t a t i o n
operations.
5 90.233
Secondary b a s e l m o b i l e nonvoice s i g n a l i n g o p e r a t i o n s .
On a secondary b a s i s t o v o i c e o p e r a t i o n s , t h e use o f A2, A9, F2, F9 (audiofrequency t o n e s h i f t o r t o n e phase
s h i f t ) o r F9Y emission may be a u t h o r i z e d t o b a s e l m b i l e o p e r a t i o n s i n accordance w i t h t h e f o l l o w i n g l i m i t a t i o n s
and requirements:
(a)
A u t h o r i z a t i o n s a r e l i m i t e d t o m o b i l e s e r v i c e f r e q u e n c i e s below 950 MHz.
( b ) Maximum d u r a t i o n of a t r a n s m i s s i o n f o r each d i s t i n c t non-voice message, i n c l u d i n g automatic r e p e a t s of
t h e message, may n o t exceed 2 seconds. There must be a break i n t h e c a r r i e r between each such t r a n s m i s s i o n .
( c ) Required s t a t i o n i d e n t i f i c a t i o n f o r non-voice o p e r a t i o n s must be made by F3 o r A3 emission and may be
g i v e n by t h e base s t a t i o n f o r a baselmobile system.
( d ) Secondary non-voice o p e r a t i o n s under t h i s s e c t i o n may n o t be a u t h o r i z e d f o r tone paging, t e l e m e t r y ,
r a d i o l o c a t i o n , AVM, r a d i o t e l e p r i n t e r , r a d i o f a c s i m i l e , o r r a d i o c a l l box o p e r a t i o n s .
These o p e r a t i o n s a r e
a u t h o r i z e d under o t h e r s e c t i o n s o f t h i s p a r t .
6 90.235
Secondary f i x e d t o n e s i g n a l i n g and a l a r m o p e r a t i o n s .
I n t h e Local Government, P o l i c e , F i r e , Highway Maintenance, F o r e s t r y Conservation, Power, and Petroleum Radio
Radio Services, f i x e d o p e r a t i o n s may be a u t h o r i z e d f o r t o n e o r impulse s i g n a l i n g on m o b i l e s e r v i c e f r e q u e n c i e s above
25 MHz w i t h i n t h e area n o r m a l l y covered by t h e l i c e n s e e ' s m o b i l e system on a secondary b a s i s t o t h e p r i m a r y m o b i l e
s e r v i c e o p e r a t i o n o f any o t h e r l i c e n s e e f o r t h e purposes d e s c r i b e d i n paragraphs ( a ) and ( b ) :
(a)
I n t h e P u b l i c S a f e t y Radio Services, t h e o n l y purposes f o r which such secondary s i g n a l i n g may be used a r e :
(1)
I n d i c a t i o n o f equipment m a l f u n c t i o n .
A c t u a t i o n o f a d e v i c e t o i n d i c a t e t h e presence o f an i n t r u d e r , f i r e , o r o t h e r hazardous c o n d i t i o n on t h e
p r o p e r t y under t h e p r o t e c t i o n o f t h e l i c e n s e e .
(2)
( 3 ) I n d i c a t i o n o f an abnormal c o n d i t i o n i n f a c i l i t i e s under t h e j u r i s d i c t i o n o f t h e l i c e n s e e t h a t , i f n o t
p r o m p t l y r e p o r t e d , would r e s u l t i n danger t o human l i f e .
(4)
Transmissions t h a t may be necessary t o v e r i f y s t a t u s o f equipment; a d j u s t o p e r a t i n g c o n d i t i o n s ; c o r r e c t
any abnormal c o n d i t i o n ; o r t o a c t i v a t e d e v i c e s t h a t a l e r t t h e p u b l i c t o a c o n d i t i o n a f f e c t i n g t h e i m n i n e n t
safety o f l i f e o r property.
( 5 ) C o n f i r m a t i o n o f s t a t u s , when an o p e r a t i o n o r c o r r e c t i o n has been accomplished, o r when an a l e r t i n g d e v i c e
has been a c t i v a t e d .
( b ) I n t h e Power and Petroleum Radio S e r v i c e s , t h e o n l y purposes f o r . w h i c h such secondary s i g n a l i n g may be
used are:
(1)
I n d i c a t i o n o f f a i l u r e o f equipment o r s e r v i c e used i n t h e f a c i l i t i e s o f t h e l i c e n s e e .
I n d i c a t i o n o f an abnormal c o n d i t i o n i n t h e p r o d u c t i o n , t r a n s m i s s i o n , c o l l e c t i o n , d i s t r i b u t i o n , r e f i n i n g ,
(2)
o r t r a n s p o r t i n g f a c i l i t i e s o f t h e l i c e n s e e , which i f n o t p r o m p t l y c o r r e c t e d would r e s u l t i n f a i l u r e of t h e equipment a f f e c t e d .
( 3 ) Transmission from t h e p o i n t where alarms o r o t h e r o p e r a t i o n a l d a t a a r e r e c e i v e d as may be necessary t o
v e r i f y s t a t u s o f equipment o r processes; v e r i f y o r a d j u s t o p e r a t i n g c o n d i t i o n s ; r e s t o r e l o s t s e r v i c e ; p l a c e
standby equipment i n o p e r a t i o n ; o r t o c o r r e c t any abnormal c o n d i t i o n s which would o t h e r w i s e r e s u l t i n t h e
immediate o r c o n t i n u e d f a i l u r e i n t h e l i c e n s e e ' s o p e r a t i o n s .
( 4 ) Confirmation of s t a t u s o r o p e r a t i n g c o n d i t i o n s , o r t h a t an o p e r a t i o n o r c o r r e c t i o n intended t o be
accomplished i n subparagraph ( 3 ) o f t h i s paragraph has occurred.
(c)
A l l such secondary s i g n a l i n g s h a l l be s u b j e c t t o t h e f o l l o w i n g t e c h n i c a l requirements:
(1)
The bandwidth s h a l l n o t exceed t h a t a u t h o r i z e d t o t h e l i c e n s e e f o r t h e primary operations on t h e
frequency concerned.
(2)
The o u t p u t power s h a l l n o t exceed 30 w a t t s ( a t t h e remote s i t e ) .
(3)
A l , A2, A9, F1, F2, and F9 emission may be a u t h o r i z e d .
I n t h e P o l i c e Radio S e r v i c e A3 o r F3 emission
may a l s o be authorized.
( 4 ) For systems a u t h o r i z e d i n t h e P u b l i c S a f e t y Services a f t e r June 20, 1975, t o be used f o r t h e purposes
out1 ined i n paragraph ( a ) o f t h i s s e c t i o n , t h e maximum d u r a t i o n o f any one nonvoice s i g n a l may n o t exceed 2
seconds and s h a l l n o t be t r a n s m i t t e d more than t h r e e times.
The maximum d u r a t i o n o f any one v o i c e alarm s h a l l
n o t exceed 6 seconds and s h a l l n o t be t r a n s m i t t e d more than t h r e e times.
For systems a u t h o r i z e d p r i o r t o t h i s
date, any one alarm o r warning may be t r a n s m i t t e d a maximum o f f i v e times and each transmission
s h a l l n o t exceed
6 seconds; such system t o i n c l u d e e x i s t i n g f a c i l i t i e s and a d d i t i o n a l f a c i l i t i e s which may be authorized as a
c l e a r and d i r e c t expansion o f t h e e x i s t i n g system.
( 5 ) For systems a u t h o r i z e d i n t h e Petroleum Radio S e r v i c e a f t e r June 1, 1976, each transmission f o r any
one alarm, warning c o r r e c t i v e a c t i o n , o r requirement, p o s i t i v e c o n f i r m a t i o n , checkback, o r o t h e r purpose s e t
f o r t h i n paragraph ( b ) o f t h i s s e c t i o n , s h a l l be l i m i t e d t o a maximum d u r a t i o n o f 2 seconds and s h a l l n o t be
repeated more than t h r e e times.
For systems a u t h o r i z e d p r i o r t o June 1, 1976, any one alarm o r warning may
be t r a n s m i t t e d a maximum o f f i v e times and each transmission may n o t exceed 6 seconds; such- systems t o i n c l u d e
e x i s t i n g f a c i l i t i e s and a d d i t i o n a l f a c i l i t i e s which may be a u t h o r i z e d as a c l e a r and d i r e c t expansion o f t h e
e x i s t i n g system.
( 6 ) For systems a u t h o r i z e d i n t h e Power Radio S e r v i c e a f t e r June 1, 1976, each transmission f o r any one
alarm, warning c o r r e c t i v e a c t i o n , o r requirement, p o s i t i v e c o n f i r m a t i o n , checkback, o r o t h e r purpose s e t f o r t h
i n paragraph ( b ) o f t h i s s e c t i o n , s h a l l be l i m i t e d t o a maximum d u r a t i o n o f 2 seconds and s h a l l n o t be repeated
more than f i v e times.
For systems a u t h o r i z e d p r i o r t o June 1, 1976, any one alarm o r warning may be t r a n s m i t t e d
a-maximum o f f i v e times and each t r a n s m i s s i o n may n o t exceed 6 seconds; such systems t o i n c l u d e e x i s t i n g
f a c i l i t i e s and a d d i t i o n a l f a c i l i t i e s which may be a u t h o r i z e d as a c l e a r and d i r e c t expansion o f t h e e x i s t i n g
system.
(7)
Systems employing
automatic i n t e r r g a t i o n s h a l l be l i m i t e d t o nonvoice techniques and s h a l l n o t be
a c t i v a t e d f o r t h i s purpose more than 10 seconds o u t o f any 60-second p e r i o d .
This 10 second timeframe i n c l u d e s
both t r a n s m i t and response times.
( 8 ) Frequency l o a d i n g r e s u l t i n g from t h e use o f secondary s i g n a l i n g w i l l b o t be considered i n whole
o r i n p a r t as a j u s t i f i c a t i o n f o r a u t h o r i z i n g a d d i t i o n a l frequencies i n t h e l i c e n s e e ' s m o b i l e system.
( 9 ) A mobile s e r v i c e frequency may n o t be used e x c l u s i v e l y f o r secondary s i g n a l i n g .
(10) Automatic means s h a l l be provided t o d e a c t i v a t e t h e t r a n s m i t t e r i n t h e event t h e c a r r i e r remains on f o r
a p e r i o d i n excess o f 3 minutes.
( 1 1 ) Operational f i x e d s t a t i o n s a u t h o r i z e d pursuant t o t h e p r o v i s i o n s o f t h i s paragraph a r e exempt from t h e
requirements o f 88 90.137(b), 90.425 and 90.429.
(12) Base, mobile r e l a y , o r m o b i l e s t a t i o n s may t r a n s m i t secondary tone o r impulse s i g n a l s t o r e c e i v e s
a t f i x e d l o c a t i o n s s u b j e c t t o t h e c o n d i t i o n s , and f o r t h e purposes s e t f o r t h i n t h i s s e c t i o n .
8 90.469
(a)
Unattended o p e r a t i o n .
Subject t o t h e p r o v i s i o n s o f 5 8 90.243,
90.245, and 90.247, mobile r e l a y , f i x e d r e l a y , and m o b i l e
r e p e a t e r s t a t i o n s are a u t h o r i z e d f o r unattended operation; and t h e t r a n s m i t t e r c o n t r o l p o i n t requirements
set out a t
58
90.463 through 90.465 s h a l l n o t apply.
( b ) S e l f - a c t i v a t e d t r a n s m i t t e r s may be a u t h o r i z e d f o r unattended o p e r a t i o n where t h e y a r e a c t i v a t e d by
e i t h e r e l e c t r i c a l o r mechanical devices, provided t h e l i c e n s e e adopts reasonable means t o guard a g a i n s t malfunct i o n s and harmful i n t e r f e r e n c e t o o t h e r users.
Appendix C.
INPUT/OUTPUT DESCRIPTION RAMP CONTROLLER
DESCRIPTION OF EXTERNAL INPUTS
TITLE
REFERENCE
FUNCTION PERFORMED
LEVEL I N 0
LEVEL I N 1
LEVEL I N 2
P1-34
P1-35
P1-36
B i n a r y encoded i n p u t s from remote
computer t o f o r c e segmenter l e v e l
CLOCK I N
P1-33
I n p u t s i g n a l from 24 hour t i m e
c l o c k t h a t i s used i n c o n j u n c t i o n
w i t h mode s e l e c t o r t o determine
c o n t r o l l e r operation
QUEUE I N
DEMAND IN
MERGE I N
FREEWAY I N
P1-23
P1-25
P1-27
P1-29
I n p u t s from v e h i c l e presence
detectors
ON LINE CONTROL
P1-30
C o n t r o l i n p u t from remote computer
MANUAL PB
P1-48
I n p u t from manual push b u t t o n f o r
s i g n a l advance
AUTO/MANUAL
P1-49
C o n t r o l i n p u t t o s e l e c t manual mode
o p e r a t i o n when t r u e
BY-PASS DEMAND I N
SPARE I N 1
SPARE I N 2
SPARE I N 3
SPARE I N 4
P1-32
P1-19
P1-31
P1-46
P1-47
Reserved f o r f u t u r e expansion
NOTES:
1. A l l i n p u t s use ground t r u e l o g i c f o r s t a t e c o n d i t i o n .
2. B i n a r y encoding f o r segment l e v e l s a r e as f o l l o w s :
SEGMENT
LINE 2
LINE 1
LINE 0
A
B
C
D
E
0
0
0
0
1
0
0
1
1
X
0
1
0
1
X
O=FALSE
l=TRUE
X=DONT CARE
DESCRIPTION OF EXTERNAL OUTPUTS
TITLE
REFERENCE
PERCENT
PERCENT
PERCENT
PERCENT
PERCENT
PERCENT
PERCENT
0
1
2
3
4
5
P1- 8
PI- 9
PI-10
P1-11
FUNCTION PERFORMED
B i n a r y encoded o u t p u t o f
freeway occupancy percentage
( 0 t o 100%)
6
LEVEL OUT 0
LEVEL OUT 1
LEVEL OUT 2
B i n a r y encoded o u t p u t o f segment
1eve1 t o remote computer
Output o f v e h i c l e presence
d e t e c t o r s t o remote computer
GREEN CONFIRM
Green s i g n a l c o n f i r m o u t p u t t o
remote computer
VOLUME
VOLUME
VOLUME
VOLUME
VOLUME
VOLUME
VOLUME
B i n a r y encoded o u t p u t of
freeway volume t o remote
computer
0
1
2
3
4
5
6
FLASH SIG 0
FLASH SIG 1
Output s i g n a l d r i v e r s f o r t h e
advance warning f l a s h e r s
GREEN SIG
AMBER SIG
RED SIG
Output d r i v e r s f o r t h e ramp
metering control signal l i g h t s
BY PASS DEMAND OUT
BY PASS GREEN
BY PASS AMBER
BY PASS RED
SPARE OUT 1
Reserved f o r f u t u r e expansion
APPENDIX D.
TUESDAY AM Approx. 7 :00 AM
s t a t i o n s performed n o r m a l l y .
8:00 AM - o p e r a t i o n a l .
TUESDAY AIY
NOON 11-1.
LOG OF RF TEST
-
TIME PERIODS
Clear - Cool - Approx. 4 3 ' ~ . A1 1
Checked D i s t r i c t 2 p r i n t e r by Telephone a t
- 8:50 AM.
Clear
-
Warm.
A l l s t a t i o n s O.K.
Checked p r i n t e r O.K.
...........................................................................
TLIESDAY PM S t a r t e d 3 : 15. Accident I B caused queuing on OB 1anes. Upstream
ramps came on because o f c l o c k and occupancy r e a d i n g * Had t o s t o p approx.
3:30 - 3:45. Restarted approx. 6:00 PM. Clear - 63 F. Observed a t t r a n s m i t t e r s i t e downstream queuing was n o t e v i d e n t a t 30% occupancy ( 1 min average)
o u t s i d e l a n e f l o w i n g 1850-1900. A l l o v e r l o a d i n g a t U n i v e r s i t y and upstream
o f t h i s p o i n t due t o 3 lanes t o two ( 2 ) lanes drop. U n i v e r s i t y has r a t h e r
l a r g e , 1 ong a c c e l e r a t i o n l a n e . Completely d a r k a t 7:00 PM. Slave 2 ( F o r e s t
Park) b i t s 1 and 3 sometimes do n o t g e t changed t o new s t a t e u n t i l t h e 2nd
t r a n s m i s s i o n . Do n o t know what i s c a u s i n g problem. T h i s t y p e o f problem
has been r e p o r t e d a t a1 1 3 s t a t i o n s . ( I n v e s t i g a t e t h i s phenomenon \ l l i t h L a r r y
Burgess (SECODE)). Hope p r i n t e r has p l e n t y o f tape.
WEDNESDAY AM S t a r t e d 6:15 AM. Dark - Cloudy - 5 3 ' ~ . Summit and F o r e s t Park
c o n t r o l l e r s c o n s i s t e n t l y a r e changing on 2nd t r a n s m i s s i o n - do n o t know why
t h i s i s happening. No o u t r i g h t f a i l u r e s have been e v i d e n t . A l l independent
o u t d o o r a d v e r t i s i n g s i g n s a r e o f f . Approx. 7:45 - Had t o s t o p t r a n s m i t t i n g
f o r 3 t o 4 minutes w h i l e p r i n t e r t a p e supply was replaced. Approx. 8:25 Study Ended.
*
WEDNESDAY NOON S t a r t e d 1 1 : O O AM. Cloudy - 6 5 ' ~ - S l i g h t wind. A l l s t a t i o n s
N o t i c e d d i s t i n c t i v e b i t changing a t Summit where a l l b i t s change
appear O.K.
on 2nd t r a n s m i s s i o n . Not always p r e d i c t a b l e . Remainder o f s t u d y went w i t h o u t
-incident.
.............................................................................
WEDNESDAY PM S t a r t approx. 3:05 PM. Cloudy - S l i g h t wind. Sent 4 s e t s .
Stopped approx. 4:15.
Back on a t 5:40 PM. Sundown 6:15. A l l s i g n s on by
6:30.
No problems o f s k i p p i n g occurred.
THURSDAY AM S t a r t e d approx. 6:35 AM. 5 0 ' ~ - Fog. Problem o f 2nd t o n e @
Summit and F o r e s t Park. Voice r a d i o communications bad between same and
Montgromery ( t r a n s m i t t e r s i t e ) . L i g h t s on Summit 6:53. 7:00 F o r e s t Park
Lots o f i n t e r f e r e n c e w i t h Wal k i e - T a l k i e s throughout t h e p e r i o d . IYany 2nd
tones. Probl'em a t U n i v e r s i t y w i t h 2 b i t s f o r c e d on a f t e r d a t a s e t s 5, 1,
2, and p a r t s o f 3, 6, 7 have o n l y 2 b i t changes. Good.
-
Hot - Sunny - 7 1 ' ~ - Clear. Same
THURSDAY NOON S t a r t e d approx. 11:20 AM.
2nd tones a t U n i v e r s i t y , F o r e s t Park and Summit. It seemed t o improve w i t h
time. A t 1:23 t h e s t u d y ended. It was d i s c o v e r e d t h a t t h e volume o f t h e RF
Received c o u l d c o n t r o l t o n e decoding.