AN OVERVIEW OF
RANDOM BREATH TESTING
OPERATIONS
IN VICTORIA 1989-1991
by
GLENN SULLlV AN
ANTONIETTA CAVALLO
ALAN DRUMMOND
October 1992
Report No. 40
MONASH UNIVERSITY ACCIDENT RESEARCH CENTRE
REPORT DOCUMENTATION PAGE
Report No.
40
Report Date
October 1992
ISBN
0732600405
Pages
21
Title and sub-title:
An overview of Random Breath Testing Operations in Victoria 1989-1991.
Author(s):
Type of Report & Period Covered:
Sullivan, G.
Cavallo, A.
Drummond, A.E.
GENERAL, 1989-1991
Sponsoring Organisation:
Transport Accident Commission
222 Exhibition Street
Melbourne VIC 3000
Abstract:
Towards the end of 1989 the Victoria police took deliveryof13 highly visible, purpose-built buses from
which to conduct RBT operations. Prior to that testing had been primarily car-based. Operational data
from the initiative have been made available to monitor the changes in police operations as the initiative
evolved. RBT operational data from July 1989 to June 1991, covering the period where buses were
introduced, have been used to monitor these changes.
The main change in RBT activity over the two years was the increased usage of buses and the resultant
decrease in car-based testing. In the metropolitan area the change to buses was almost immediate while
the introduction of buses to rural Victoria was much slower and varied across police districts.
The introduction of buses has led to increases in the number ofRBT tests and gradual, but relatively
smaller, increases in the total number of hours of RBT operations and session duration in the
metropolitan area. In the rural areas the number of tests and duration ofRBT sessions have, until early
1991, remained relatively constant. The number of hours spent testing in rural areas has varied over
time.
The main change due to the introduction of buses for the purpose ofRBT has been a large increase in
the number of people tested for only small changes in the total time spent testing.
KeyWords:
(IRRD except when marked*)
evaluation (assessment), collision,
road trauma, enforcement,
Blood Alcohol Content, alcohol *,
drink driving *, Random Breath Testing*
Disclaimer:
This report is disseminated in the interests of
information exchange. The views expressed are
those of the authors, and not necessarily those of
Monash University.
Reproduction of this page is authorised.
AN OVERVIEW OF RANDOM BREATH TESTING OPERATIONS
...
111
Contents
ACKNOWLEDGEMENTS
VII
EXECUTIVE SUMMARy
IX
1.0
INTRODUCTION
1
2.0
RBT INITIATIVE - OPERATIONAL DATA
1
2.1
RBT Operations Statewide
1
2.2
RBT in Metropolitan and Rural Victoria
3
2.2.1
2.2.2
Hours of RBT testing
Number of RBT tests
3
3
2.2.3
2.2.4
2.2.5
Car and bus-based RBT operations
RBT session duration
Start/end times ofRBT sessions
.4
7
12
2.2.6
2.2.7
2.2.8
RBT by day of week
PBT
Hit rates
16
17
17
2.3
2.4
RBT in Police Districts
19
2.3.1
2.3.2
19
20
Hours spent RBT testing and numbers of tests conducted
Car and bus-based operations
Summary of RBT Operations
REFERENCES
21
21
Appendix A Location of Metropolitan and rural police districts
Appendix B RBT Operations in Police Districts
AN OVERVIEW OF RANDOM BREATH TESTING OPERATIONS ...
V
Acknowledgements
This analysis of Random Breath Testing operations was made
possible by the provision of data by
Victoria Police staff of the Traffic Alcohol Section.
AN OVERVIEW OF RANDOM BREATH TESTING OPERATIONS
...
VU
EXECUTIVE
SUMMARY
Since its inception in 1976, random breath testing (RBT) operations had been
primarily car-based. As part ofthe RBT Initiative (commencing towards the end
of 1989), the Victoria Police took progressive delivery of 13 highly visible,
purpose built buses from which to conduct RBT operations. Operational data
from the initiative have been made available to monitor the changes in police
operations as the initiative evolved. RBT operational data from July 1989 to June
1991, covering the period where buses were introduced, have been used to
monitor these changes.
The main change in RBT activity over the two years was the increased usage of
buses and the resultant decrease in car-based testing. In the metropolitan area the
change to buses was almost immediate while the introduction of buses to rural
Victoria was much slower and varied across police districts.
The introduction of buses has led to increases in the number of RBT tests and
gradual, but relatively smaller, increases in the total number of hours of RBT
operations and session duration in the metropolitan area. In the rural areas the
number of tests and duration of RBT sessions have, until early 1991, remained
relatively constant. The number of hours spent testing in rural areas has varied
over time.
The main change due to the introduction of buses for the purpose ofRBT has been
a large increase in the number of people tested for only small changes in the total
time spent testing.
AN OVERVIEW OF RANDOM BREATH TESTING OPERATIONS •..
IX
1.0 INTRODUCTION
Random Breath Testing (RBT) originally was introduced to Victoria in 1976 and involved
random breath testing drivers, for alcohol levels, from police cars. Towards the end of 1989
the Victoria police began to use highly visible, purpose-built buses from which to conduct RBT
operations. Previously testing was primarily car-based, although four Toyota Coaster buses
were also used. Operational data from July 1989 to June 1991 was made available to monitor
the changes brought about by the introduction of bus-based RHT testing.
The RHT initiative has been evaluated to determine the effect the program has had on road
accidents (Drummond, Sullivan & Cavallo, 1992; Cameron, Cavallo & Sullivan, 1992;
Cavallo & Cameron, 1992). The operational data was essential to understand the exact nature
of the program and to undertake the post-hoc quasi-experimental evaluation.
The extensive analysis of operational data also provides feedback to the agencies implementing
the initiative. This report provides a summary of RBT operations with graphical representations of the data.
2.0 RBT INITIATIVE - OPERATIONAL DATA
An examination of the characteristics of RBT and a description of its operation in the period
from July 1989 to June 1991 for different areas in Victoria was undertaken to assist the
evaluation of its effectiveness. The characteristics available for examination were:
2.1
•
the number of hours of testing;
•
the number of tests conducted;
•
the ratio of bus-based and car-based RBT;
•
session duration;
•
time of day and day of week of operation; and
•
the number of drivers detected with a positive reading.
RBT Operations Statewide
Information regarding RBT and preliminary breath testing (PBT) operations in each police
district in Victoria was obtained for the two year period from July 1989 to June 1991. PBT
operations involve mobile intercepts and tests of drivers involved in crashes.
Between July 1989 to June 1991 there were:
17,625 RBT sessions
over 23,000 hours ofRBT testing
almost 1.8 million RBT tests
The number of RBT tests steadily increased over the two years while, at the same time, PBT
testing appeared to decrease somewhat after 1989 (Figure 2.1).
AN OVERVIEW OF RANDOM BREATH TESTING OPERATIONS
...
Figure 2.1 RBT & PBT Tests
I_RBT
300000
S
ste 150000
125000
July
250000
T 50000
200000
225000
175000
275000
0
25000
100000
75000
to
'89
Sep
OPBT I
to
Qet
'89
Dee
Jan
to
April
July
to
Qct
Jan
to
to
to
to
Mar
June
Sep
Dee
Mar
June
'90
'90
'90
'90
'91
'91
April
In contrast, hours of testing overall remained relatively constant, apart from increases when the
RBT initiative was first introduced (last quarter 1989) and at the beginning of 1991 (Figure
2.2).
The number of RBT tests conducted in Victoria since 1977 progressively increased over time
with a substantial increase from around 1;2 million tests in 1989 to over 900,000 in 1990 and 1.1
million in 1991 as a result of the initiative.
Figure 2.2 RBT: Hours of Testing
4500
2500
2000
1500
H
0
1000
3000
500
3500
4000
sour
'89
to
Sep
to
'89
Dec
Qet
July
Jan
to
Mar
'90
2
MONASH UNIVERSITY
April
to
June
'90
Sep
Qct
to
Dec
'90
'90
July
to
ACCIDENT RESEARCH CENTRE
Jan
to
Mar
'91
April
to
June
'91
2.2
RBT in Metropolitan and Rural Victoria
In this study the metropolitan area is defined as police districts A to J, whilst remaining police
districts (K to Q) constitute rural areas. Maps of areas of the State which make up the
metropolitan and rural police districts appear in Appendix A.
2.2.1 Hours of RBT testing
Overall, the total number of hours ofRBT testing was greater in rural Victoria (14,000 hours)
than in the Melbourne metropolitan area (9,000 hours) over the two years. However, in the
metropolitan area hours of testing gradually increased to a level of around 480 hours per month
by 1991, whilst in the rural area, the number of hours spent testing was more variable,
decreasing throughout most of 1990. There were intensified efforts in rural Victoria in January
and March 1991 however, with over 1000 hours of testing in each month (Figure 2.3).
Figure 2.3 RBT - Monthly Number of Hours of Testing
1--
Metropolitan -
Rest of State
I
1200
1000
,800
H
o
u
600
r
s
400
200
o
J
A
1989
SON
D
J
F
M
A
M
J
J
1990
A
SON
D
J
F
M
A
M
J
1991
2.2.2 NumberofRBTtests
Overall, the metropolitan area had a much greater number of tests (1.2 million tests) than the
rural area (~million tests). The number of persons tested in the metropolitan area generally
increased (to about 70,000 tests per month) while the numbers tested in the rural area remained
steady at around 20,000 tests per month (Figure 2.4).
AN OVERVIEW OF RANDOM BREATH TESTING OPERATIONS
...
3
Figure 2.4 RBT - Monthly Number of Persons Tested
1---
Rest of State I
Metropolitan -
80000
70000
P 60000
e
r
550000
o
n
5 40000
T
e
5 30000
t
e
d 20000
10000
o
J
A
SON
0
J
F
M
A
1989
M
J
J
A
SON
1990
0
J
F
M
A
M
J
1991
2.2.3 Car and bus-based RBT operations
In late 1989, 13 new buses were purchased and fitted for the purpose of conducting RBT tests.
The main differences between bus and car-based RBT testing is that there are more police
personnel operating each bus and the capacity for RBT testing is therefore increased.
Calculations for the two year period show that bus-based RBT operations more than doubled
the testing rate of car-based RBT operations in both the metropolitan (154 tests per hour from
buses and 70 tests per hour from cars) and rural areas (89 tests per hour from buses and 31 tests
per hour from cars).
There was a steady increase in both the proportion of RBT tests conducted and hours spent
testing out of buses. RBT testing in the metropolitan area shifted from being primarily carbased (80 to 90% of hours between July-September 1989) to almost completely bus-based,
with cars accounting for less than 10% of hours, by September 1990 (Figures 2.5 and 2.6). In
the metropolitan area bus-based RBT was the primary form of RBT operation since November
1989 in terms of both hours of testing and number of tests conducted.
4
MONASH
UNIVERSITY
ACCIDENT RESEARCH CENTRE
Figure 2.5 Metropolitan RBT Tests
o Sus
'_car
100%
80%
60%
40%
20%
0%
J
A
SON
D
J
F
M
A
M
1989
J
J
A
SON
F
D
M
A
M
J
1991
1990
Figure 2.6 Metropolitan RBT Hours
o
I_car
Sus
100%
80%
60%
40%
20%
0%
J
1989
A
SON
D
F
M
A
M
J
1990
J
A
SON
0
F
M
A
M
1991
AN OVERVIEW OF RANDOM BREATH TESTING OPERATIONS ...
5
In contrast, RBT testing in the rural area changed from being almost completely car-based to
a level in which cars accounted for about 60% ofRBT hours by June 1991 (Figures 2.7 and 2.8).
The trend of shifting towards buses in the rural area appeared to be continuing at the end of the
two years.
Figure 2.7 Rural RBT Tests
o
I_car
J
A
SON
D
F
M
A
M
1989
Sus
J
A
SON
D
F
M
A
M
J
1991
1990
Figure 2.8 Rural RBT Hours
o
I_ear
Sus
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
J
A
SON
0
1989
6
MONASH
J
F
M
A
M
J
J
A
SON
1990
UNIVERSITY
ACCIDENT RESEARCH
0
J
F
M
A
M
1991
CENTRE
J
2.2.4 RBT session duration
RBT session duration in the metropolitan area: There was an increase in session duration
over the two year time period as shown by the shifting distribution (Figures 2.9 to 2.12) and also
the average durations (Figure 2.13) for six monthly periods.
In the period from July to
December 1989 the majority of sessions were under I hour in duration. The number of longer
sessions increased over time, with the majority of sessions lasting from I% to 3 hours and also
greater than 5 hours by mid-1990 and 1991. This trend was consistent with the gradual increase
in hours of operation over time and the number of sessions remaining relatively constant.
Figure 2.9 Metropolitan Session Duration Jut to Dee 1989
250
200
S
e 150
5
5
i
o
n 100
5
50
> to
la
to
300
1610
mins
4610
mins
mins
mins
75
10
31
240
180
300
270
120
105
90
30
60
45
10
9110
7610
151
181
271
210
150
211
6110
121
241
106
0
1 to
Figure 2.10 Metropolitan
Session Duration Jan to Jun 1990
250
200
S
e 150
5
5
I
o
n 100
5
50
0
300
to
10
la
to
90
75
45
to
mins
105
1610
6110
9110
7610
4610
30
60
121
241
271
270
240
180
300
120
211
3110
151
181
106
210
150
mins
mins
110
AN OVERVIEW OF RANDOM BREATII TESTING OPERATIONS
...
7
Figure 2.11 Metropolitan Session Duration Jul to Dee 1990
250
200
5
e 150
s
s
i
o
n 100
s
50
0
300
180
to
30
90
45
to> to
mins
mins
210
150
300
270
240
120
16to
31
61
105
75
60
76
151
91
181
46
106
to
241
121
211
271
110
Figure 2.12 Metropolitan Session Duration Jan to Jun 1991
250
200
5
e 150
s
s
I
o
n 100
s
50
0
mins
120
300
to
mins
1610
31
270
240
210
61
180
300
151
241
to
211
181
271
106to
90
75
45
150
46
to
91
121
105
30
60
76
110
8
MONASH
UNIVERSITY
ACCIDENT RESEARCH CENTRE
, I
Figure 2.13 Metropolitan
Area Mean Session Duration
180
160
140
120
M
I
100
n
u
t
e
80
5
60
40
20
o
Jut to Dec '89
Jan to Jun '90
Jul to Dec '90
Jan to Jun '91
RBT session duration in the rural area: Session duration did not change greatly (Figures
2.14 to 2.17). The vast majority of sessions in rural Victoria were less than I hour in duration,
although, in the first half of 1991 there was an increase in the number of sessions greater than
five hours in duration. The average session duration decreased until the first half of 1991
(Figure 2.18).
Figure 2.14 Rural Session Duration Jut to Dec 1989
1200
1000
600
I se 400
S 0n
200
800
o
1 to
15
mms
'T1:ns
mi;,S
rTllnS
7'.3
45 tot8
16
'31
3D
46
31
to
le
'''IriS
Figure 2.15 Rural Session Duration Jan to Jun 1990
S 0sneI
s
1200
400
600
1000
800
200
0
> to
to
30
300
45
to
16to
91
181
150
180
120
105
75
90
60
31
76
61
121
211
46
151
106
to
mins
mins
210
300
240
mins
241
271
270
1 to
Figure 2.16 Rural Session Duration Jul to Dee 1990
1200
1000
800
600
I
S 05ne 400
200
0
300
to
16to
mins
105
30
75
mms
121
211
181
61
91
271
241
151
106
mins
210
150
300
270
240
180
90
31
76
46
45
60
to to
to
mins
120
1 to
10
MONASH
UNIVERSITY
ACCIDENT RESEARCH CENTRE
Figure 2.17 Rural Session Duration Jan to Jun 1991
1200
1000
800
600
400
I
S 0sne
200
0
> to
31
mins
mins
10
150
120
10
mins
90
181
241
271
106
16to
6110
46
to
210
270
180
240
300
mins
300
105
75
60
45
121
211
151
76
30
91
110
Figure 2.18 Rural Area Mean Session Duration
90
80
70
60
M
150
n
u
et
40
s
30
20
10
o
Jul to Dec '89
Jan to Jun '90
AN
Jul to Dec '90
Jan to Jun '91
OVERVIEW OF RANDoM BREATH TESTING OPERATIONS
...
11
Bus and car-based session duration: Whilst the average session duration of buses operating
in the rural area remained at around two hours, the distribution has changed over time with an
increase in the number of bus sessions less than one hour and also greater than five hours. The
duration of bus sessions in the metropolitan area did not change over the two year period with
a mean duration of over 3 hours. Car session duration was also steady over the period in both
the metropolitan and rural areas with the majority of sessions being under 1 hour in duration.
The increase in session duration in the metropolitan area appeared to be the result ofthe shift
from predominantly car-based operations to almost totally bus-based operations which were
typically longer in duration. Since the shift towards buses was slower in the rural area the
introduction of the buses had relatively little effect on session duration in these areas until the
first half of 1991.
2.2.5 Start/end times of RBT sessions
The start times in the metropolitan area did not greatly change with a median start time between
7pm and 8pm. Over that time period RBT operations tended to finish later with the median
finish time shifting from about 9pm in the last six months of 1989 to 11pm in the first six months
of 1991 (Figures 2.19 to 2.22). It appeared that the increase observed in session duration in
the metropolitan area was the result of the sessions running later. There was a reduction in the
level of testing during late morning and early afternoon.
In the rural area the start and end times ofRBT sessions did not greatly change. (Figures 2.23
to 2.26).
Figure 2.19 Metropolitan Start/End Times Jul to Dee 1989
I_
0
Start Hour
End Hour
250
200
S
e 150
s
s
i
o
n 100
s
50
o
o
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Hour Beginning
12
MONASH
UNIVERSITY
ACCIDENT
RESEARCH
CENTRE
15
16
17
18
19
20
21
22
23
Figure 2.20 Metropolitan StartJEnd Times Jan to Jun 1990
I_
Start Hour
0
End Hour
10
12
13
250
200
S
e 150
5
5
I
'0
n 100
5
50
o
o
1
2
3
4
S
6
7
8
9
11
14
1S
16
17
18
19
20
21
22
23
21
22
23
Hour Beginning
Figure 2.21 Metropolitan StartJEnd Times Jut to Dee 1990
I_
Start Hour
D End Hour
250
200
S
e 1S0
5
5
I
o
n 100
5
50
o
o
1
2
3
4
S
6
7
8
9
10
11
12
13
14
1S
16
17
18
19
20
Hour Beginning
AN OVERVIEW OF RANDOM BREATH TESTING OPERATIONS
...
13
Figure 2.22 Metropolitan StartlEnd Times Jan to Jun 1991
I_
0
Start Hour
End Hour
250
200
S
e 150
s
s
i
o
n 100
s
50
o
o
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
20
21
22
23
Hour Beginning
Figure 2.23 Rural StartlEnd Times Jul to Dec 1989
I_
0
Start Hour
End Hour
700
5i
n
0300
0
e400
200
S
0
100
500
600
2
14
MONASH
3
4
5
UNIVERSITY
6
7
8
9
10
11
Hour
Beginning
12
13
14
ACCIDENT RESEARCH CENTRE
15
16
17
18
19
Figure 2.24 Rural StartlEnd Times Jan to Jun 1990
/_
start Hour
0 End
Hour
700
S
n
5I
0
°300
e400
200
0
100
600
SOD
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
20
21
22
23
Hour Beginning
Figure 2.25 Rural Start/End Times Jul to Dee 1990
I_
0 End
start Hour
Hour
700
sesnI 400
0300
0
S 200
100
0
600
500
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
Hour Beginning
AN OVERVIEW OF RANDOM BREATH TESTING OPERATIONS
...
15
Figure 2.26 Rural StartlEnd Times Jan to Jun 1991
\_
0
Start Hour
End Hour
700
600
500
S
5e 400
5
i
0300
n
5
200
100
o
o
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Hour Beginning
2.2.6 RBT by day of week
In the metropolitan area Thursday, Friday and Saturday are the days with the highest number
of hours of RBT testing. RBT operations became even more concentrated on these days as
compared to the earlier part of the week (Figure 2,27) although there were substantial periods
of time spent testing on each day of week. The emphasis of time spent in rural RBT testing
shifted from Friday, Saturday and Sunday to be more in line with the metropolitan area (Figure
2.28).
Figure 2.27 Metropolitan RBT Hours by Day of Week
•
Jul to Dec '89
0
Jan to Jun '90
_
Jul to Dec '90
0
Jan to Jun '91
600
5u0r 300
H
16
200
1000
400
500
Sunday
MONASH
Monday
UNIVERSITY
Tuesday
Wednesday
ACCIDENT RESEARCH CENTRE
Thursday
Friday
Saturday
Figure 2.28 Rural RHT Hours by Day of Week
IIIJul to Dec '89 0 Jan to Jun '90
H s
ur
0
1000
400
500
•
Jul to Dec '90
0 Jan to Jun '91
Sunday
1000
200
300
900
700
800
600
Monday
Tuesday
Wednesday
Thursday
Friday
Saturday
2.2.7 PBT
There is very little information available about PBT tests (tests from mobile intercepts and
crash involved drivers) conducted in the two year period except for the number tested in
metropolitan and country areas each month. It should be noted that metropolitan and country
are Police definitions and differ slightly from the definitions used previously.
Of the 919,450 PBT tests conducted 62% occured in metropolitan areas while the remaining
38% ofPBT tests were in country Victoria.
2.2.8 Hit rates
The RBT hit rate (percentage of positive BAC tests) in the metropolitan area over the two year
period (0.25 to 0.40%) was consistently higher than in rural Victoria (0.10 to 0.15%) as shown
in Figure 2.29. For both areas the hit rate varied somewhat over this period with no clear upward
or downward trends. The hit rate for PBT (3 to 4%) is much higher than for RBT but, as with
RBT, there was no obvious trend (Figure 2.30).
AN OVERVIEW OF RANDOM BREATH TESTING OPERATIONS ...
17
Figure 2.29 RBT Hit Rate (Positive BAC) - Metropolitan v. Rural
1_
Metropolitan
-
Rest of Stat~
I
0.50
0.45
0.40
0.35
%
P 0.30
o
5
I 025
t
i
0.20
V
e
0.15
0.10
0.05
0.00
A
J
SON
D
F
M
A
M
A
J
SON
D
J
F
M
A
M
1991
1990
1989
Figure 2.30 PBT Hit Rate (Positive BAC) - Metropolitan v. Country
1-
Metropolitan -
Country
6.00
5.00
%
4.00
p
o
sI 3.00
t
I
v
e 2.00
1.00
0.00
A
J
SON
0
1989
18
MONASH
F
M
A
M
J
A
SON
1990
UNIVERSITY
ACCIDENT RESEARCH CENTRE
0
F
M
A
M
1991
2.3
RBT in Police Districts
2.3.1 Hours spent RBT testing and numbers ottests conducted
The number of hours spent testing and the total number of RBT tests conducted within each
police district were examined (Figures 2.31 and 2.32).
Figure 2.31 Hours ofRBT Testing
,_
Division 1
0
Division 2
3500
3000
2500
H 2000
o
u
r
51500
1000
500
o
AB
CD
E
F
G
K
H
L
M
N
0
P
a
0
P
a
Rest of State
Metropolitan
Figure 2.32 RBT Tests
I_
Division 1
0
Division 2
250000
200000
150000
T
e
5
t
5
100000
50000
o
AB
C
D
E
Metropolitan
F
G
H
K
L
M
N
Rest of State
AN OVERVIEW OF RANDOM BREATH TESTING OPERATIONS
...
19
Districts in the metropolitan area spent similar amounts of time RBT testing and conducted
similar numbers of tests per hour (Figure 2.33). In districts A, B and C there were more tests
conducted each hour, in comparison to other districts. This can be explained by the higher
traffic volumes in these districts which are located in and around the inner metropolitan area.
Districts D, E and F recorded the lowest number of tests per hour.
Figure 2.33 RBT - Rate of Testing in Police Districts
I_
Division 1
0
Division 2
160
140
T 120
•
s
t 100
s
P 80
•
r
H 60
o
u
r 40
20
o
A
BeD
E
F
G
H
K
M
N
0
P
Q
Rest of state
Metropolitan
In the different rural police districts there was marked variation in the number of hours spent
testing and the number of tests conducted. When broken down into the different divisions it
can be seen that the majority ofRBT in some rural districts was concentrated mainly in one of
the divisions, generally the one closer to Melbourne. This is most evident in districts M and
0, the two districts immediately north west of the metropolitan area.
2.3.2 Car and bus-based operations
The introduction of buses occurred almost immediately in all of the metropolitan police
districts while their introduction to rural areas was slower and at varying times across police
districts. Some rural districts/divisions began introducing buses early in 1990 while other
districts/divisions first began to use them in late 1990 or early 1991.
A detailed analysis of the number and proportion of hours and tests conducted from car and busbased operations, for each individual police district, is presented in Appendix B.
In closely scrutinising the amount of bus use in the different police districts and divisions it
appears that the type of RBT in a district can be categorised into one of three models. The
metropolitan districts were all similar, in that they moved to buses very quickly. In the rural
area there appeared to be some districts/divisions that introduced low levels of bus based RBT
in late 1989/early 1990 with the remaining areas making very little use of buses until, at least,
late 1990.
20
MONASH
UNIVERSITY
ACCIDENT
RESEARCH CENTRE
2.4
Summary of RBT Operations
The main change in RBT activity over the two years was the increased usage of buses and the
decrease in car-based RBT. The introduction of buses almost immediately substituted carbased RBT in all police districts in the metropolitan area while their introduction in the rural
area was much slower and varied across police districts.
This led to a much higher number of RBT tests and gradual, but relatively smaller, increases
in the total number of hours ofRBT operations and session duration in the metropolitan area.
In rural Victoria, the number ofRBT tests conducted and the duration ofRBT sessions (until
1991) remained relatively constant, even though the number of hours spent testing was variable
over time. In some rural areas bus-based RBT was used at low levels whilst at the remaining
rural locations bus-based RBT was not used consistently until late 1990/early 1991. Overall
in Victoria this resulted in a substantial increase in the number of RBT tests for only gradual
changes in the time spent testing.
REFERENCES
Cameron, M.H., Cavallo A., & Sullivan, G. 1992, Evaluation of the Random Breath Testing
Initiative in Victoria 1989-1991. Multivariate Time Series Approach, Report No. 38, Monash
University Accident Research Centre, Clayton, Victoria
Cavallo, A., & Cameron, M.H. 1992,Evaluation of a Random Breath Testing Initiative in
Victoria 1990 & 1991. Summary Report, Report No. 39, Monash University Accident
Research Centre, Clayton, Victoria
Drummond, A.E., Sullivan, G., & Cavallo, A. 1992, Evaluation of a Random Breath Testing
Initiative in Victoria 1989-1990. Quasi-experimental time series approach, Report No. 37,
Monash University Accident Research Centre, Clayton, Victoria
AN OVERVIEW OF RANDOM BREATH TESTING OPERATIONS ...
21
Appendix A
Location of Metropolitan and
Rural Police Districts
,,~
flt'B~
pI
MOUNTAINS
2
~
-",..r
1
LEGEND
-
DISTRIcr BOUNDARIES
DIVISIONAL BOUNDARIES
z.-'
..
I
I
I
I
N
I
I
I
j
i
I
!
I
1
\
I
I
1
1
I
i
2
I
iI
iI
I
j
I
!
I
I
i
M
2
i!
IllGHLANDS WIMMERA
e ••.•••.••••
.......•..
~~.
Q
"
.
....
'.
2
17/
./
W
\}
LEGEND
DISTRICT BOUNDARIES
DIVISIONAL BOUNDARIES
Appendix B
RBT Operations in Police Districts
-j;-
Police District A
Number of RBT tests from Cars and Buses
I Dear
•
Bus
J
A
8000
6000
4000
2000
o
A
J
SON
0
F M
J
A
M
J
SON
0
J
F M
A M
J
July 89 - June 91
Police District A
Proportion of RBT tests from Cars and Buses
I Dear
•
Bus
100%".-
11
90"k
80%
70%
60%
I
50%
40%
20"k
10%
J
A
SON
0
J
F M
I
I
30%
A M
J
J
A
July 88- June 81
SON
0
J
F M
A M
J
Police District A
Number of Minutes of Car and Bus based RBT
I Dear
•
I
Bus
I
.r
If
Ir
r.r.orIrrI.r
•
1
I
~
r
71
6000
5000
4
3000
.~
2
J
ASONDJ
FMAMJ
J
ASONDJ
FMAMJ
July 89 - June 91
Police District A
Proportion of Car and Bus based RBT Minutes
loear
100o/in
•
I
Bus
III
6O"1c
40%
20%·
~
J
A SON
0 J
F M A M J
J
A SON
July 89 - June 91
0 J
.-lj
F M A M J
Police District B
Number of RBT tests from Cars and Buses
loeM
•
Bus
I
8000
6000
4000
2000
o
J
ASONDJ
FMAMJ
J
ASONDJ
FMAMJ
July 89 - June 91
Police District B
Proportion of RBT tests from Cars and Buses
IOear
• Bus
100%,.,.-
60%
I
20%
J
A
SON
D
J
F
M
A
M
J
J
A
July 89 - June 91
SON
D
J
F
M
A
M
J
Police District B
Number of Minutes of Car and Bus based RBT
IDear
•
I
Bus
9000
8000
7000
6000
5000
4000
3000
2000
o
J
ASONDJ
FMAMJ
J
ASONDJ
FMAMJ
July 89 • June 91
Police District B
Proportion of Car and Bus based RBT Minutes
locar
•
Bus
-
l00%~
90%
80%
70%
60%
50%
40%
30%
20%
10%
J
A
SON
D
J
F
M
A
M
July
J
811 •
J
A
June III
SON
D
J
F
M
A
M
J
Police District C
Number of RBT tests from Cars and Buses
IOcar
•
Bus
8000
6000
4000
o
J
A
SON
0
J
F
M
A
M
J
J
A
SON
0
J
F
M
A
M
J
F
M
A
M
J
July89-June91
Police District C
Proportion of RBT tests from Cars and Buses
ID Car
•
Bus
100%
80%
60%
40%
20%
0%
J
A
SON
0
J
F
M
A
M
J
J
A
July 811· June 111
SON
0
J
Police District C
Number of Minutes of Car and Bus based RBT
I Dear
•
I
Bus
9000
8000
7000
6000
5000
4000
3000
2000
o
J
ASONDJ
FMAMJ
J
ASONDJ
FMAMJ
July 89 • June 91
Police District C
Proportion of Car and Bus based RBT Minutes
IOear
• Bus
I
100%
80%
60%
40%
20%
0%
J
ASONDJ
FMAMJ
J
ASONDJ
July 88 • June 81
FMAMJ
Police District D
Number of RBT tests from Cars and Buses
jocar
•
Bus
8000
6000
4000
o
J
ASONDJ
FMAMJ
J
ASONDJ
FMAMJ
July 89 - June 91
Police District D
Proportion of RBT tests from Cars and Buses
I Dear
•
Bus
100%'
80%
60%
40%
20%
0%
J
A
SON
0
J
F
M
A
M
J
J
A
July 811-Junelll
SON
0
J
F
M
A
M
J
Police District D
Number of Minutes of Car and Bus based RBT
.Bus
IDear
I
9000
8000
7000
6000
5000
4000
3000
2000
o
J
ASONDJ
FMAMJ
J
ASONDJ
FMAMJ
July 89 - June 91
Police District D
Proportion of Car and Bus based RBT Minutes
10 Car
I
• Bus
100"10
80%
60%
40%
20%
0%
J
ASONDJ
FMAMJ
J
ASONOJ
July 89 - June 81
FMAMJ
Police District E
Number of RBT tests from Cars and Buses
I o ear
• Bus
I
8000
6000
4000
2000
o
J
ASONDJ
FMAMJ
J
ASONDJ
FMAMJ
July 89 • June 91
Police District E
Proportion of RBT tests from Cars and Buses
I o ear
• Bus
I
100%
80%
60%
40%
20%
0%
J
ASONDJ
FMAMJJASONDJ
July 88 • June 81
FMAM,'
'-t::'.-.:~.
Police District E
Number of Minutes of Car and Bus based RBT
I DCar
• Bus
I
9000
8000
7000
5000
4000
3000
2000
o
A
J
SON
0
J
F M
A M
J
A
J
SON
0
J
F M
A
M
J
F M
A M
J
July 89 - June 91
Police District E
Proportion of Car and Bus based RBT Minutes
I o ear
I
• Bus
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
J
A
SON
0
J
F M
A M
J
J
A
July 89 - June 91
SON
0
J
Police District F
Number of RBT tests from Cars and Buses
I o ear
• Bus
8000
6000
4000
2000
o
J
A
SON
D
J
F
M
A
M
J
J
A
SON
D
J
F
M
July 89 - June 91
Police District F
Proportion of RBT tests from Cars and Buses
I Dear
100%,..,-,
,-,
_
,-,
_
30%
80%
40%
50"k
60%
90%
70%
0%
20%~
;;
10%-H
11 11 I 1 I.
J
; ~;
ASONDJ
; ~;
r; ~;
1 I.
; ~
~
•
Bus
III
I 11 11 11 I ••
FMAMJ
J
ASONDJ
July 89 - June 91
FMAMJ
A
M
J
Police District F
Number of Minutes of Car and Bus based RBT
I Dear
.Sus
I
9000
8000
7000
6000
5000
4000
3000
2000
1000
o
J
ASONDJ
FMAMJJ
ASONDJ
FMAMJ
July 89 • June 91
Police District F
Proportion of Car and Bus based RBT Minutes
I Dear
100%,.,......, .--
r-
•
I
Bus
r-
90%
-
80%
70%
60%
50%
40%
30%
20"'{'
10%
J
A
SON
D
J
F
M
A
M
J
J
A
July 89 • June 91
SON
0
J
F
M
A
M
J
Police District G
Number of RBT tests from Cars and Buses
IDear
•
Bus
I
8000
6000
4000
2000
o
J
ASONDJ
FMAMJ
J
ASONDJ
FMAMJ
July 89 • June 91
Police District G
Proportion of RBT tests from Cars and Buses
I Dear
•
Bus
40%
20%
00;;'
J
ASONDJ
FMAMJ
J
July
1111
•
ASONDJ
June 111
FMAMJ
Police District G
Number of Minutes of Car and Bus based RBT
IDear
•
I
Bus
9000
8000
7000
6000
5000
4000
3000
2000
o
J
A
SON
0
J
F
M
A
M
J
J
A
SON
0
J
F
M
July 89 - June 91
Police District G
Proportion of Car and Bus based RBT Minutes
I Dear
•
I
Bus
60%
40%
20%
0%
J
ASONDJ
FMAMJ
J
ASQNDJ
July 88 - June 81
FMAMJ
A
M
J
Police District H
Number of RET tests from Cars and Buses
Io ear
• Sus
I
8000
6000
4000
o
J
ASONDJ
FMAMJ
J
ASONDJ
FMAMJ
July 89 - June 91
Police District H
Proportion of RBT tests from Cars and Buses
I Dear
•
Bus
100%
90"k
80%
70%
60%
50%
40%
30%
20%
10%
0%
J
ASONDJ
FMAMJ
J
ASONDJ
July 88 • June III
FMAMJ
Police District H
Number of Minutes of Car and Bus based RBT
I DCar
.Bus
I
9000
8000
7000
6000
5000
4000
3000
2000
1000
o
J
ASONDJ
FMAMJ
J
ASONDJ
FMAMJ
July 89 • June 91
Police District H
Proportion of Car and Bus based RBT Minutes
100%
80%
60%
40%
20%
0%
J
A
SON
0
J
F
M
A
M
J
J
A
July 88 - June 81
SON
0
J
F
M
A
M
J
Police District I
Number of RBT tests from Cars and Buses
loear
•
Bus
J
A
I
8000
6000
4000
2000
o
J
A SON
0
J
F M
A M
J
SON
0
J
M
A
M
J
F M
A
M
J
F
July 89 • June 91
Police District I
Proportion of RBT tests from Cars and Buses
I
°
ear
• Bus
•
90%
•
80%
100%1
70%
60%
50%
40%
30%
20%
-
-
10%
4J
J
A SON
0
J
F M
A M
J
J
A
July 88 • June 81
SON
n
0
J
Police District I
Number of Minutes of Car and Bus based RBT
I Dear
.Sus
I
9000
8000
7000
6000
5000
4000
3000
2000
o
J
ASONDJ
FMAMJ
J
ASONDJ
FMAMJ
July 89 - June 91
Police District I
Proportion of Car and Bus based RBT Minutes
JOcar
I
• Bus
I··············
100%]1130%
40%
50%
80%
60%
90%
10%
0%
200k
70%
•
III I'-Ir-"
J
A
SON
0
J
F
M A
M
J
J
A
July 88 - June III
SON
0
J
F
M
A
M
J
Police District J
Number of RBT tests from Cars and Buses
I o Car
• Bus
8000
6000
4000
o
A
J
SON
D
F M
J
A
M
J
J
A
SON
D
J
F M
A M
J
F M
A M
J
July 89 - June 91
Police District J
Proportion of RBT tests from Cars and Buses
IOear
•
Bus
100%
80%
60%
40%
20%
0%
J
A
SON
D
J
F M
A M
J
J
A
July 89 - June 91
SON
D
J
Police District J
Number of Minutes of Car and Bus based RBT
I Dear
•
Bus
9000
8000
7000
6000
5000
4000
3000
2000
o
JASONDJFMAMJJASONDJ
FMAMJ
July 89 • June 91
Police District J
Proportion of Car and Bus based RBT Minutes
I Dear
•
Bus
I
100%
80%
60%
40%
20%
0%
JASONDJFMAMJJASQNDJ
FMAMJ
July
811- June
111
Police District Kl
Number of RBT tests from Cars and Buses
loear
•
Bus
I
8000
6000
4000
2000
o
J
ASONDJ
FMAMJ
JASONDJ
FMAMJ
July 89 - June 91
Police District Kl
Proportion of RBT tests from Cars and Buses
I o ear
• Bus
I
100%
80%
60%
40%
20%
0%
J
ASONDJ
FMAMJ
J
ASONDJ
July 811- June 111
FMAMJ
Police District Kl
Number of Minutes of Car and Bus based RBT
10 Car
I
• Bus
9000
8000
7000
6000
5000
4000
3000
2000
1000
o
A
J
SON
0
J
F M
A M
J
A
J
SON
0
J
F M
A M
J
F M
A M
J
July 89 • June 91
Police District Kl
Proportion of Car and Bus based RBT Minutes
-
100"10
--
~-
10
Car
~
-
I
• Bus
80%
60%
-
40%
20%
0%
J
A
SON
0
J
F M
A M
J
J
A
July 89 • June 91
SON
0
J
Police District K2
Number of RBT tests from Cars and Buses
IOear
•
Bus
J
A
8000
6000
4000
2000
o
A
J
SON
0
J
F
M
A
M
J
SON
0
J
F
M
A
M
J
F
M
A
M
J
July 89 • June 91
Police District K2
Proportion of RBT tests from Cars and Buses
100''<'
-
--
r-
-
r-
J
A
SON
-
I o ear
- -
• Bus
I
r-
80%
60%
40%
20%
0%
0
J
F
M
A
M
J
J
July811-Junelll
A
SON
0
J
Police District K2
Number of Minutes of Car and Bus based RBT
I DCar
• Bus
I
9000
8000
7000
6000
5000
4000
3000
2000
1000
o
J
ASONOJ
FMAMJ
J
ASONOJ
FMAMJ
July 89 • June 91
Police District K2
Proportion of Car and Bus based RBT Minutes
I
I Dear
---.
r- -
100%
•
I
Bus
-
r- - - .r-I
~
40%
20%
0%
J
A
SON
0
J
F
M
A
M
J
J
A
July 89 • June 91
SON
0
J
F
M
A
M
J
Police District Ll
Number of RBT tests from Cars and Buses
IDear
•
Bus
J
A
8000
6000
4000
o
A
J
SON
0
J
F
M
A
M
J
SON
0
J
F
M
A
M
J
F
M
A
M
J
July 89 - June 91
Police District L 1
Proportion of RBT tests from Cars and Buses
I Dear
100% ,.
•
Bus
•
- -r---- -~
90010
1""'\
80%
70%
60%
50%
40%
30%
20010
10%
0%
J
A
SON
0
J
F
M
A
M
J
J
A
July 89 - June 91
SON
0
J
Police District L 1
Number of Minutes of Car and Bus based RBT
I Dear
•
Bus
J
A
9000
8000
7000
6000
5000
4000
3000
2000
1000
o
J
A
SON
D
J
F
M
A
M
J
SON
D
J
F
M
July 89 • June 91
Police District Ll
Proportion of Car and Bus based RBT Minutes
I Dear
100% ;-
•
Bus
••
--'--1
- - ;-
90%
;-
80%
70%
60%
~
50%
40%
30%
20%
10%
0%
JASONDJFMAMJJASONDJ
FMAMJ
July 88 - June 81
A
M
J
Police District L2
Number of RBT tests from Cars and Buses
IDear
•
Sus
I
8000
6000
4000
o
J
ASONDJ
FMAMJ
J
ASONDJ
FMAMJ
July 89 - June 91
Police District L2
Proportion of RBT tests from Cars and Buses
100%
-
90%
I
IOear
- --- • --
r-
•
Bus
~
80%
70%
60%
-
50%
40%
30%
20%
10%
0"10
J
ASONDJ
FMAMJ
J
ASONDJ
July 89 - June 91
FMAMJ
Police District L2
Number of Minutes of Car and Bus based RBT
I o ear
• Sus
9000
8000
7000
6000
5000
4000
3000
2000
1000
o
J
ASONDJ
FMAMJ
J
ASONDJ
FMAMJ
July 89 - June 91
Police District L2
Proportion of Car and Bus based RBT Minutes
• Bus
I Dear
1 OO%-rr---1
,---,
r-l .-. ,......,
,---,r-l ,--, r--l
r--'1 r--
~roroll·
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
J
ASONDJ
FMAMJ
J
ASONDJ
July 89 • June 81
FMAMJ
Police District Ml
Number of RBT tests from Cars and Buses
IOear
I
Sus
J
A
8000
6000
4000
2000
o
J
A
SON
D
J
F
M
A
M
J
SON
0
J
F
M
July 89 • June 91
Police District Ml
Proportion of RBT tests from Cars and Buses
-
100%
~
I
•••
-c--c-.c-
90%
10 Car
• Bus
• 1-·
80%
-
70%
60%
50%
40%
20%
10%
0%
JASONDJ
FMAMJ
J
ASONDJ
July 88 ·June81
FMAMJ
A
M
J
Police District Ml
Number of Minutes of Car and Bus based RBT
I,
I., I,
..
I,11.
I,
t
}
I. I.
I
I Dear
I
•
Bus
I
8
7
6000
5000
4,
3
2
L
J
ASONDJ
FMAMJ
J
ASONDJ
FMAMJ
July 89 - June 91
Police District Ml
Proportion of Car and Bus based RBT Minutes
IDear
•
Bus
I
100%
------II~I-I-.-
-
III
80%
60%
40%
20%
0%
J
ASONDJ
FMAMJ
J
July
ASONDJ
all- June III
FMAMJ
Police District M2
Number of RBT tests from Cars and Buses
IDear
•
Bus
8000
6000
4000
2000
o
J
ASONDJ
FMAMJ
J
ASONDJ
FMAMJ
July 89 - June 91
Police District M2
Proportion of RBT tests from Cars and Buses
-•
- --r~--- --
I Dear
•
Bus
-
80%
60%
40%
20%
0%
J
ASONDJ
FMAMJ
JASONDJ
July 811- June 91
FMAMJ
Police District M2
Number of Minutes of Car and Bus based RBT
I Dear
•
Sus
9000
8000
7000
6000
5000
4000
3000
2000
o
J
ASONDJ
FMAMJ
J
ASONDJ
FMAMJ
July 89 - June 91
Police District M2
Proportion of Car and Bus based RBT Minutes
100%
-
I
-
- --r-
-
rr-r-
J
A
90%
I Dear
-
•
Bus
80%
70%
60%
50%
40%
30%
20%
10%
0%
SON
0
J
F
M
A
M
J
J
A
July 89 - June 91
SON
0
J
F
M
A
M
J
Police District NI
Number of RBT tests from Cars and Buses
I Dear
•
Bus
8000
6000
4000
2000
o
J
ASONDJ
FMAMJ
J
ASONDJ
FMAMJ
July 89 • June 91
Police District NI
Proportion of RBT tests from Cars and Buses
100%
-
I Dear
-
•
Bus
-- -
r-~
80%
60%
40%
20%
0%
J
A
SON
0
J
F
M
A
M
J
J
A
July 88 - June 91
SON
0
J
F
M
A
M
J
Police District NI
Number of Minutes of Car and Bus based RBT
IDear
•
Bus
J
A
9000
8000
7000
6000
5000
4000
3000
2000
1000
o
A
J
SON
0
J
F M
A
M
J
SON
0
J
F
M
A M
J
F M
A M
J
July 89 - June 91
Police District NI
Proportion of Car and Bus based RBT Minutes
100%
-- --
IOear
•
Bus
•
r-
r-
r----
r--
J
A
SON
600/0
40%
20%
0%
0
J
F M
A
M
July
J
J
ae • June
A
81
SON
0
J
Police District NZ
Number of RBT tests from Cars and Buses
10 Car
• Bus
8000
6000
4000
2000
o
J
A
SON
D
J
F M
A M
J
J
A
SON
D
J
F
M
A M
J
A
J
July 89 - June 91
Police District N2
Proportion of RBT tests from Cars and Buses
100%
•
I
~
-;-- - .--
jocar
•
Bus
.--
60%
60%
40%
20%
0%
J
A SON
D
J
F M
A M
J
J
A
July 89 - June 91
SON
D
J
F M
M
Police District N2
Number of Minutes of Car and Bus based RBT
IDear
•
Bus
9000
8000
7000
6000
sooo
4000
3000
2000
1000
o
J
ASONDJ
FMAMJ
J
ASONDJ
FMAMJ
July 89 • June 91
Police District N2
Proportion of Car and Bus based RBT Minutes
100%
II
- r--r~--- -
-
~r
• Bus
-
80%
60%
40%
20%
J
A
SON
D
J
F
M
A
M
J
J
A
July 89· June 91
SON
0
J
F
M
A
M
J
Police District 01
Number of RBT tests from Cars and Buses
I ° Car
• Bus
8000
6000
.4000
o
J
A
SON
D
J
F
M
A
M
J
J
A
SON
D
J
F
M
A
M
J
July 89 • June 91
Police District 01
Proportion of RBT tests from Cars and Buses
~ar
100%
• Sus
'_~---~-- -
• I
80%
60%
40%
20%
0%
J
ASONDJ
FMAMJ
J
ASONDJ
July 89 • June 91
FMAMJ
Police District 01
Number of Minutes of Car and Bus based RBT
I Dear
•
Bus
I
6000
5000
4
3
2
.
I,
I,I,I,
I. •I,.,
I.
.
0
,
A
J
SON
I, .,
F
J
M
A
M
J
J
A
SON
0
J
F
M
A
M
J
July 89 • June 91
Police District 01
Proportion of Car and Bus based RBT Minutes
I o ear
• Sus
I
I
100%
90%
·--~·~--~II-IIIIII
-.
80%
70%
60%
50%
40%
30%
20%
10%
0%
J
A
SON
0
J
F
M
A
M
J
J
A
July 89 - June 91
SON
0
J
F
M
A
M
J
Police District 02
Number of RBT tests from Cars and Buses
IOear
•
Bus
8000
6000
4000
o
J
ASONDJ
FMAMJ
J
ASONDJ
FMAMJ
July 89 - June 91
Police District 02
Proportion of RBT tests from Cars and Buses
100%
-- -
--r- r-
.--re.--- r-
I Dear
•
Bus
-
~
80%
60%
40%
20%
0%
J
ASONDJ
FMAMJ
J
ASONDJ
July 89 - June 91
FMAMJ
Police District 02
Number of Minutes of Car and Bus based RBT
I DCar
• Bus
I
9000
8000
7000
6000
5000
4000
3000
2000
1000
o
J
ASONDJ
FMAMJ
J
ASONDJ
FMAMJ
July 89 • June 91
Police District 02
Proportion of Car and Bus based RBT Minutes
100%
- ~-
I DCar
• Bus
-
,..--r--r--~
-~I
80%
40%
20%
0%
J
ASONDJ
FMAMJ
J
ASONDJ
July 811· June III
FMAMJ
Police District PI
Number of RBT tests from Cars and Buses
I DCar
• Bus
I
8000
6000
4000
o
J
ASONDJ
FMAMJ
J
ASONDJ
FMAMJ
July 89 - June 91
Police District PI
Proportion of RBT tests from Cars and Buses
100%
I
IOcar
,- -~-~ -~-~-
I I
80%
60%
•
Bus
-
,
20%
0%
J
A
SON
0
J
F
M
A
M
J
J
A
July 89 - June 91
SON
0
J
F
M
A
M
J
Police District PI
Number of Minutes of Car and Bus based RBT
IDear
•
Bus
I
9000
8000
7000
6000
5000
4000
3000
2000
1000
o
J
ASONDJ
FMAMJ
J
ASONDJ
FMAMJ
July 89 - June 91
Police District PI
Proportion of Car and Bus based RBT Minutes
I DCar
100%n-0 ~
~
•
•
Bus
n n n n n ~ n n Inn
I~
11~nil
40%
20%
J
ASONDJ
FMAMJ
JASONDJ
July 89 • June 91
FMAMJ
Police District P2
Number of RBT tests from Cars and Buses
I
I o Car
Sus
8000
6000
4000
o
A
J
SON
0
F
J
M
A
M
J
A
J
SON
0
J
F
M
A
M
J
F
M
A
M
J
July 89 - June 91
Police District P2
Proportion of RBT tests from Cars and Buses
I Dear
100%
----
1-
•
r--
Bus
-
-
80%
60%
40%
,~,
-
20%
0%
J
A
SON
0
J
F
M
A
M
J
J
July 89 - June
A
111
SON
0
J
Police District P2
Number of Minutes of Car and Bus based RBT
jocar
•
Bus
9000
8000
7000
6000
5000
4000
3000
2000
1000
o
A
J
SON
D
F M
J
A M
J
J
A
SON
D
J
F
M
A
M
J
F M
A
M
J
July 89 - June 91
Police District P2
Proportion of Car and Bus based RBT Minutes
I Dear
100%
--~-II-I
•
Bus
-- - -
80%
-
60%
40%
20%
0%
J
A
SON
D
J
F M
A M
J
J
A
July 89 • June 81
SON
D
J
Police District Q 1
Number of RBT tests from Cars and Buses
IOear
•
Bus
8000
6000
4000
2000
o
J
A
SON
0
J
F
M
A
M
J
J
A
SON
0
J
F
M
July 89 - June 91
Police District Ql
Proportion of RBT tests from Cars and Buses
,-80%
II
IOear
-- - -,--,--
•
Bus
~
60%
40%
20%
0%
J
ASONDJ
FMAMJ
J
ASONDJ
July 89 - June 91
FMAMJ
A
M
J
Police District Q 1
Number of Minutes of Car and Bus based REI
IDear
•
Bus
I
9000
8000
7000
6000
5000
4000
3000
2000
1000
o
J
A
SON
0
J
F
M
A
M
J
J
A
SON
0
J
F
M
July 89 - June 91
Police District Q 1
Proportion of Car and Bus based RBT Minutes
-
100%
10
-
Car
• Bus
--r--r---~~
1- -
11
80%
P""'\
60%
40%
20%
J
ASONDJ
FMAMJ
J
ASONDJ
July 811• June III
FMAMJ
A
M
J
Police District Q2
Number of RET tests from Cars and Buses
IDear
•
Bus
8000
6000
4000
o
J
ASONDJ
FMAMJ
J
ASONDJ
FMAMJ
July 89 • June 91
Police District Q2
Proportion of RBT tests from Cars and Buses
100% r-
--
I o ear
- -~
-
• Bus
r-
90%
80%
70%
60%
50"10
40%
30%
~
20%
10%
0%
J
A
SON
0
J
F
M
A
M
J
J
A
July 89 • June 91
SON
0
J
F
M
A
M
J
Police District Q2
Number of Minutes of Car and Bus based RBT
IDear
•
Bus
9000
8000
7000
6000
5000
4000
3000
2000
o
J
A
SON
0
J
F
M
A
M
J
J
A
SON
0
J
F
M
A
M
J
F
M
A
M
J
July 89 • June 91
Police District Q2
Proportion of Car and Bus based RBT Minutes
100%
r-
I
--r-
r-
-
80%
I
• Bus
-
-
60%
10 Car
i
40%
20%
0%
J
A
SON
0
J
F
M
A
M
J
J
A
July 89 - June 91
SON
0
J