Knoxville Regional Travel Demand Model
Upgrade Program
May 6, 2004
Agenda
 TAZ Database
 External Trips
 Roadway Network
 Network Editing Tools
 Speed Capacity Estimation
 Signal Impedance
 Model Interface
 Trip Generation
 Trip Distribution
 Vehicle Occupancy & Time of Day
 Traffic Assignment
 Resolution of Calibration Issues &
Final Validation Statistics
 Post-Processing
Expanded Study Area
Traffic Analysis Zones
 Total of 747 TAZ
 717 Internal zones
 30 External zones
 45 Data Attributes
 Demographic data from
Census 2000
 Employment by 10 major
industry classes
 University student
enrollment & residence
 K-12th grade enrollments
External Trips
 30 External Stations
 34,000 daily trips
 Five Interstates
Average 25.2%
through
 21 Other Stations
Average 1.2%
through
External Trips (Cont’d)
9001 9002 9003 9004 9005 9006 9007 9008 9009 9010 9011 9012 9013 9014 9015 9016 9017 9018 9019 9020 9021 9022 9023 9024 9025 9026 9027 9028 9029 9030
9001
0
5
9
402
0
27
2
9
0
89
0
0 2027
0
0 1715
0
8
0
0
11
3
6
76
1
138
0
0
0
11
9002
5
0
0
15
0
0
0
0
0
1
0
0
24
0
0
4
0
0
0
0
0
0
0
0
0
16
0
0
0
0
9003
9
0
0
4
0
0
0
0
0
0
0
0
13
0
0
6
0
0
0
0
0
0
0
0
0
18
0
0
0
0
9004
402
15
4
0
4
6
0
4
0
16
0
0
14
0
0
812
0
3
0
0
22
2
11
36
1 3991
0
0
0
0
9005
0
0
0
4
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
2
0
0
0
0
9006
27
0
0
6
0
0
0
0
0
0
0
0
2
0
0
5
0
0
0
0
1
0
1
0
0
112
0
0
0
0
9007
2
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
3
0
0
0
0
9008
9
0
0
4
0
0
0
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
7
0
0
0
0
9009
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
9010
89
1
0
16
0
0
0
0
0
0
0
0
9
0
0
21
0
0
0
0
2
0
3
0
0
170
0
0
0
0
9011
0
0
0
0
0
0
0
0
0
0
0
0
3
0
0
3
0
0
0
0
0
0
0
0
0
0
0
0
0
0
9012
0
0
0
0
0
0
0
0
0
0
0
0
7
0
0
3
0
0
0
0
0
0
0
0
0
1
0
0
0
0
9013 2027
24
13
14
0
2
0
0
0
9
3
7
0
0
0
68
0
0
0
0
3
0
53
3
1 2612
0
0
0
4
0 3827
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
9014
0
0
0
0
0
0
0
0
0
0
0
0
0
9015
0
0
0
0
0
0
0
0
0
0
0
0
0 3827
9016 1715
4
6
812
0
5
0
1
0
21
3
3
68
0
0
0
0
0
0
0
2
0
4
0
0
132
0
0
0
1
9017
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
9018
8
0
0
3
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
5
0
0
4
0
0
0
0
9019
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
9020
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
9021
11
0
0
22
0
1
0
0
0
2
0
0
3
0
0
2
0
0
0
0
0
0
0
0
0
2
0
0
0
0
9022
3
0
0
2
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
9023
6
0
0
11
0
1
0
0
0
3
0
0
53
0
0
4
0
5
0
0
0
0
0
0
0
5
0
0
0
0
9024
76
0
0
36
0
0
0
0
0
0
0
0
3
0
0
0
0
0
0
0
0
0
0
0
0
4
0
0
5
0
9025
1
0
0
1
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
5
0
0
0
0
9026
138
16
18 3991
2
112
3
7
0
170
0
1 2612
0
0
132
0
4
0
0
2
0
5
4
5
0
0
0
7
6
9027
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
321
0
0
9028
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
321
0
0
0
9029
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
5
0
7
0
0
0
0
9030
11
0
0
0
0
0
0
0
0
0
0
0
4
0
0
1
0
0
0
0
0
0
0
0
0
6
0
0
0
0
4,541
64
52 5,344
6
154
6
21
0
312
6
12 4,842 3,827 3,827 2,776
0
20
0
0
42
6
88
126
8 7,235
321
321
12
23
Roadway Network
Multi-scenario Network
 Master input network
 Over 140 attributes fields containing
reference data
 Eighteen scenario-specific modeling
fields to simplify the development and
testing of different network
assumptions
 Network editing tools
 Tools for developing and managing
network scenarios
 Tools to simplify the coding of traffic
signal attributes
 Output network
 Over 170 attribute fields with detailed
outputs from the travel model and
post-processors
Roadway Network
Master Network
 Wealth of reference data
 All MINUTP model attributes
 Geographic & operational
characteristics from TRIMS
 Observed speeds from congestion
management studies
 Scenario-specific assumptions







Number of lanes by direction
Lane and shoulder widths
Presence of median
Posted speed
Access control
Area type
Traffic signalization, priority, and
synchronization
Roadway Network
Output Networks
 Scenario geometric and operational
assumptions
 Estimated free-flow speeds and
capacities
 Loaded traffic volumes by direction
and time-of-day
 Segment VMT & VHT by mode
 Average congested speeds by timeof-day
 Level of Service
 Peak 15 minute speeds and flow
densities
 VOC, CO, NOx Emissions
Network Editing Tools
Scenario Tools
 List Scenarios
 Add Scenario
 Delete Scenario
 Copy Projects
Network Editing Tools
Signal Tools
 Update Signal Fields
 Add Signals
 Delete Signals
 Import Signals from
GIS Layer
Speed & Capacity Estimation
 Free-flow speeds developed from extensive speed survey
data
 Capacity estimation based on the Highway Capacity
Manual 2000 methodologies
 Facility type = f (number of lanes, access control, presence of
median, directionality, area type)
 Free-flow speed = f (facility type, posted speed)
 Capacity = f (facility type, number of signals, approach priority,
signal synchronization, lane width, shoulder width, % heavy
vehicle, directional distribution)
Speed & Capacity Estimation
Capacity Reduction Factor for
Lateral Clearance
1.00
0.99
0.98
0.97
adjustment
factor
0.96
0.95
0.94
72.5
70
free-flow speed
67.5
65
62.5
60
57.5
55
3 ft
75
6 ft
0.92
0 ft
0.93
lateral
clearance
Signal Impedance
HCM 2000 procedure
 Delay/veh = uniform delay * PF + incremental delay + initial queue delay
where,
PF = progression factor = f (arrival type, g/C)
0.5C 1  g C 
1  min 1, v c   g C 
2
uniform delay =
 Varying g/C’s based on approach priority (higher, equal to, or lower than
cross street 0.60, 0.50, 0.40 g/C)
 Varying arrival types based on signal synchronization (isolated signal vs.
series of signals)
 Default cycle lengths = 90 sec.
Model Interface
Trip Generation
 Six internal auto trip purposes:
 HBW, HBS, HBU, HBO, NHBW & NHBO
 Trip production and attraction rates for auto mode developed
from 2000 Knoxville Household Travel Behavior Study
 Trip production:
• Predictive variables determined by non-parametric correlation analysis
• Cross-classification table dimension developed by ANOVA
 Trip attraction:
• Multivariate regression techniques
 Special university trip generation components for UT based on
1999 IU travel behavior study (both dorm based and commuter)
 Special tourist trip generation for southern Sevier County
Trip Generation (Cont’d)
Trip Production Model
Trip Purpose
1st Predictor
2nd Predictor
Trip Rate
HBW
Workers/H.H.
Vehicles/H.H.
1.21
HBS
Students/H.H.
None
0.61
HBU
University
Student/TAZ
None
0.15
HBO
Household Size
Vehicles/H.H.
3.49
NHBW
Workers/H.H.
Household Income
0.80
NHBO
Household Size
Vehicles/H.H.
1.87
Total
7.42
Trip Generation (Cont’d)
Trip Attraction Model
Trip
Purpose
Independent
Variable
Parameter
HBW
Total Employment
0.5085
HBS
K-12 Enrollment
1.7211
HBU
University Enrollment
HBO
NHBW
(Other)
Trip
Purpose
Independent
Variable
Parameter
Households
3.8321
Retail Employment
1.5399
1.1488
Office Employment
0.6419
Population
0.6778
Gov’t. Employment
0.3106
Retail Employment
2.6391
Labor Employment
1.5730
Office Employment
Gov’t. Employment
Population
Retail Employment
0.3638
0.6607
0.1758
0.6084
1.2840
1.2060
0.5140
22.8865
Office Employment
0.1244
Auto
Ex/In
Industrial Employment
Retail Employment
Office Employment
Total Employment^0.5
Households
0.2752
Gov’t. Employment
Other Employment
0.1179
0.1171
NHBW
(Work)
Total Employment
0.3567
NHBO
Trucks
Trip Distribution

Six internal trip purposes (HBW, HBS, HBU, HBO,
NHBW & NHBO) & E-I trips
 Friction Factors from 2000 Knoxville Household Travel
Behavior Study (network skims of geocoded trip ends)
 Attractions balanced to productions
 Doubly-constrained gravity model
 Socioeconomic (or K) factors to help balance county-tocounty flows and other important interactions
Trip Distribution (Cont’d)
Friction Factor Calibration for Home-Based Work
8.00
6.00
5.00
4.00
3.00
2.00
1.00
Time
BTLFD
TLFD#5
TLFD#10
TLFD#15
48
46
44
42
40
38
36
34
32
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0.00
0
Trip Length Frequency Distribution
7.00
Trip Distribution (Cont’d)
Feedback Loop for
the Knoxville
Model
Time of Day
 AM peak (7:00~9:00), PM peak (3:00~6:00), and Off-peak
 Factors for internal auto purposes from the 2000 Knoxville
Household Travel Behavior Study
 Factors for other purposes from various sources
 TOD factors to split the 24-hr trip table into tables by TOD
 TOD factors by trip purpose
 Directional factors to convert trip tables in a productionattraction format to origin-destination tables
 Directional factors by trip purpose and by TOD
Time of Day (Cont’d)
Trips by Purpose by Hour
90000
80000
HBW
70000
HBK12
60000
HBU
HBO
50000
NHBW
40000
NHBO
30000
EI
20000
EE
10000
TRK
10
8
6
4
2
12
10
8
6
4
2
12
0
Time of Day (Cont’d)
Time of Day & Directional Factors
AM
HBW
p-a
a-p
HBS
p-a
a-p
HBU
p-a
a-p
HBO
p-a
a-p
NHW
p-a
a-p
PM
27.5%
26.6%
0.9%
49.2%
49.2%
0.0%
29.8%
29.8%
0.0%
14.7%
11.8%
2.8%
16.0%
2.2%
13.9%
29.1%
2.9%
26.2%
30.0%
0.6%
29.4%
19.6%
2.5%
17.1%
25.4%
9.6%
15.8%
25.7%
21.5%
4.2%
OFF
DAILY
43.4%
100.0%
23.1%
52.6%
20.3%
47.4%
20.8%
100.0%
4.7%
54.5%
16.1%
45.5%
50.5%
100.0%
22.5%
54.9%
28.0%
45.1%
60.0%
100.0%
26.7%
48.2%
33.2%
51.8%
58.3%
100.0%
31.3%
55.0%
26.9%
45.0%
AM
NHO
p-a
a-p
EI
p-a
a-p
EE
p-a
a-p
TRK
p-a
a-p
ALL
PM
8.7%
4.3%
4.3%
7.8%
1.8%
6.0%
7.8%
3.9%
3.9%
11.0%
5.5%
5.5%
24.8%
12.4%
12.4%
20.8%
12.9%
7.8%
20.8%
10.4%
10.4%
15.0%
7.5%
7.5%
15.9%
25.3%
OFF
DAILY
66.6%
100.0%
33.3%
50.0%
33.3%
50.0%
71.4%
100.0%
35.0%
49.8%
36.4%
50.2%
71.4%
100.0%
35.7%
50.0%
35.7%
50.0%
74.0%
100.0%
37.0%
50.0%
37.0%
50.0%
58.8%
100.0%
Mode Share
Private Auto Mode Share by Purpose (from HH Survey)
HBW
HBS
HBU
HBO
NHBW
NHBO
Mode Share
98%
73%
78%
98%
98%
96%
Vehicle Occupancy
Vehicle Occupancy by Purpose by Time of Day (from HH Survey)
AM
PM
OFF
HBW
1.09
1.10
1.08
HBS
2.58
2.40
2.25
HBU
1.22
1.22
1.22
HBO
1.99
1.88
1.77
NHBW
1.09
1.16
1.20
NHBO
1.97
1.88
1.71
Traffic Assignment
 Time-of-day assignments (i.e., separate AM-peak, PM-peak & Offpeak assignments)
 Directional flows by time-of-day
 User equilibrium assignment by mode with trucks preloaded
 Calibrated volume-delay functions by functional class and
signalization
Roadway Class
Rural Interstate
Urban Interstate
Other Freeways
Rural Principal Arterials
Urban Minor Arterials
Rural Collectors
Other
Volume Delay Parameters
Alpha
Beta
8.0
4.5
0.40
2.7
0.83
2.7
Signalized
Unsignalized
Alpha
Beta
Alpha
Beta
0.7
6.0
2.0
6.0
1.8
7.0
5.5
7.0
8.0
4.5
14.0
4.5
3.0
6.0
12.0
6.0
Traffic Assignment (Cont’d)
Final Validated
Assignment
Resolution of Calibration Issues
Issue: Global Under-Loading
Solution: ODOT Factors for Trip Under-reporting
- from GPS validation of household travel surveys
Trip Purpose
Home-Based Work
Home-Based School
Home-Based University
Home-Based Other
Non-Home Based Work
Non-Home Based Other
Under-reporting Factor
1.22
1.41
1.41
1.60
2.32
2.18
Resolution of Calibration Issues
Issue: Southern Sevier County Under-Loading
Solution: Special Tourist Trip Generation
 Data on Tourism from National Park Service &
Sevier County Economic Development Council
 ITE Trip Generation Rates for Occupied Hotel
Rooms (8.17/day)
Resolution of Calibration Issues
Issue: I-40 East Over-Loading
Solution: Special Morristown
External Attractions
 Data on inter-county
flows from CTPP
journey to work data
 Convert externalinternal trip
productions to HBW
& HBO attractions
Resolution of Calibration Issues
Issue:
Over-Loading High Class Facilities &
Under-Loading Low Class Facilities
Solution: Calibrated Volume-Delay Function Parameters
Knoxville Regional-Volume Delay Curves
1.20
8.0/4.5
.40/2.7
Speed Decay
1.00
.83/2.7
0.80
0.7/6.0
0.60
1.8/7.0
0.40
8.0/4.5
3.0/6.0
0.20
2.0/6.0
0.00
0.00
5.5/7.0
0.50
1.00
1.50
V/C
2.00
2.50
14/4.5
12/6.0
Resolution of Calibration Issues
Issue:
Unbalanced Interactions between Area Types
and with External Stations
Solution: Socioeconomic (K) Factors
Average K
Factors
Final Validation Results
 All the MDOT error criteria were met
 Final Global Average Loading Error: -1.68%
 Final Global VMT Error: -0.15%
 Final Root Mean Square Error: 31.96%
Final Validation Results
Model Performance by Volume Group
Volume Range
1,001 ~ 2,000
2,001 ~ 3,000
3,001 ~ 4,000
4,001 ~ 5,000
5,001 ~ 6,000
6,001 ~ 8,000
8,001 ~ 10,000
10,001 ~ 15,000
15,001 ~ 20,000
20,001 ~ 25,000
25,001 ~ 30,000
30,001 ~ 40,000
40,001 ~ 50,000
50,001 ~ 60,000
> 60,000
ALL
Average Counts Average Loading % RMSE
1,476
2,461
3,448
4,483
5,461
7,033
8,910
12,107
17,349
22,361
27,633
33,890
43,730
57,730
66,828
11,531
2,442
3,357
3,586
4,887
5,835
7,040
8,618
11,061
15,230
20,357
26,419
33,025
42,801
59,847
70,221
11,337
153.38
101.28
71.34
69.35
49.52
45.94
44.78
33.08
25.54
21.86
17.84
13.51
11.16
17.53
8.01
31.96
% Error
% Threshold
65.45
36.39
4.01
9.02
6.85
0.10
-3.28
-8.63
-12.22
-8.96
-4.39
-2.55
-2.12
3.67
5.08
-1.68
 100
 100
 50
 50
 25
 25
 25
 20
 20
 20
 15
 15
 15
 10
 10
VMT %
Error
46.05
29.05
0.13
2.60
4.28
-1.75
-0.31
-8.63
-9.11
-4.82
-2.12
-1.34
1.16
3.29
2.58
-0.15
Final Validation Results
Model Performance by Functional Class
Functional Classification Average Counts Average Loading
Rural Interstate
Rural Prin. Arterial
Rural Minor Arterial
Rural Major Collector
Rural Minor Collector
Rural Local Roads
Urban Interstate
Urban Prin. Arterial
Urban Minor Arterial
Urban Collectors
Urban Local Roads
All
44,246
16,395
9,352
4,322
3,545
3,075
39,960
23,240
10,336
7,123
4,348
11,531
45,928
16,497
9,720
4,941
3,821
2,914
41,884
21,844
9,458
6,360
3,843
11,337
% RMSE
% Error
11.51
21.61
30.07
63.44
70.60
89.45
9.84
21.47
41.53
54.65
68.50
31.96
3.80
0.63
3.94
14.31
7.78
-5.21
4.82
-6.01
-8.50
-10.71
-11.61
-1.68
VMT %
Error
2.95
1.14
6.74
14.32
1.73
-24.74
4.51
-4.96
-10.10
-10.87
-12.98
-0.15
Final Validation Results
Model Performance by Major Corridor
Corridor
I-40
I-75
I-275
I-640
I-81
I-140
Chapman Hwy
US129
SR66/US321
Pellissippi Pkwy
SR62
Average Counts Average Loading
48,552
51,729
44,374
44,199
28,023
31,200
25,645
25,473
36,804
38,708
18,365
18,509
24,608
24,978
37,999
33,540
34,303
34,731
16,588
18,330
22,616
19,474
% RMSE
11.47
10.06
12.62
12.63
7.37
9.77
21.14
18.29
8.97
20.50
20.03
% Error
6.54
-0.39
11.34
-0.67
5.17
0.79
1.51
-11.73
1.25
10.50
-13.89
VMT % Error
4.56
1.82
12.39
0.98
4.47
-1.97
5.66
-12.20
2.54
3.81
-13.12
Final Validation Results
Model Performance by Screenline, Area Type, & County
Category
Avg Counts
Avg Loading
% RMSE
% Error
Knox County Line
Blount County Line
Screenline
Knox & Blount C.L.
Knox-Blount Border
Major Employment District
Urban Areas
Area
Type
Suburban Areas
Rural Areas
Knox County
County
Blount County
15,530
10,350
12,013
18,643
13,469
11,648
14,019
10,442
11,679
9,597
15,388
10,325
11,626
19,341
12,632
10,807
13,934
11,020
11,106
8,678
20.54
25.17
28.45
6.64
36.05
33.13
29.20
29.36
33.08
42.76
-0.91
-0.24
-3.23
3.74
-6.21
-7.22
-0.61
5.54
-4.90
-9.57
VMT %
Error
0.62
-25.63
-11.97
2.08
-5.91
-5.82
-0.99
5.33
-3.72
-6.98
Post-Processing
 POST_ALT
 Average Congested Speeds
 Level of Service
 Traffic Statistics Report
 AQ_PLuS
 Emissions by Roadway Segment
 County Total Emissions Report
 CAL_REP
 Calibration Statistics
POST_ALT: Average Speeds
 Average congested speeds by time
of day were validated against
observed speed data from
Congestion Management Studies
 32.77% RMSE for AM Speeds
 33.69% RMSE for PM Speeds
 27.98% RMSE for Off Peak Speeds
POST_ALT: Level of Service
 Level of Service based on
Highway Capacity Manual
2000 criteria by facility
type:
 Flow-Density for freeways,
expressways, & multilane
divided highways
 Percent “time spent
following” & speed decay
for rural two-lane highways
 Speed decay for urban
streets
POST_ALT: Traffic Statistics
Traffic statistics by functional class, area type, county,
and corridor - including user-defined corridors:
CLASS
MILES
VMT
AUTO_VMT
TRUCK_VMT
VHT
AUTO_VHTTRUCK_VHT
AVGSPEED DELAYPTC VC
User Corridor #1
113.55 5558630
4027241
1531389 99570
72089
27481
55.83
9808 11.0 0.72
User Corridor #2
52.76 2022129
1447251
574878 37548
26925
10623
53.85
2507
User Corridor #3
4.79 141908
124408
17500
2523
2212
311
56.24
412 16.3 0.82
User Corridor #4
20.17 511088
417142
93946
8536
6967
1569
59.88
931 10.9
0.5
User Corridor #5
7.73 297384
213151
84233
4842
3471
1371
61.42
265
6.0
0.5
User Corridor #6
21.56 364327
324035
40292
5785
5148
637
62.98
440
7.9
0.5
User Corridor #7
22.13 531549
492551
38998 11666
10827
839
45.56
1396 12.0
0.5
User Corridor #8
15.72 492116
391498
100619 10934
8707
2227
45.01
2284 20.9 0.64
User Corridor #9
21.55 745212
672106
73106 16134
14624
1510
46.19
1154
7.2 0.46
User Corridor #10
9.44 162084
132851
29232
2401
525
55.39
227
7.7 0.46
2926
7.8 0.58
AQ_PLuS: Link Emissions
Link-Specific Emissions



Volatile Organic Compounds
Carbon Monoxide
Oxides of Nitrogen
in grams/day
AQ_PLuS: County Conformity
Emissions summaries by county to facilitate
conformity determinations
Air Quality Conformity Analysis Report for Knoxville Region
from MOBILE6 and the Knoxville Regional Travel Demand Model
Mon Mar 29 02:08:59 2004
Year: 2000
Scenario: TestAQ
12748220 VMT in Knox County
Scenario:
VOC
29.26 tons/day
CO
326.91 tons/day
NOx
45.31 tons/day
Knoxville Transit Analysis Tool
Regression Model
 Predicts riders per service
hour for a route
 Using
 Population density
 Mean household income
 Average household
workers per household
vehicles
 Retail employment
density
of the area within a
quarter mile of the
route
THANK YOU!