Knoxville Regional Travel Demand Model Upgrade Program

May 6, 2004

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 TAZ717 Internal zones30 External zones

45 Data AttributesDemographic data from

Census 2000Employment by 10 major

industry classesUniversity student

enrollment & residenceK-12th grade enrollments

External Trips

30 External Stations 34,000 daily trips Five Interstates

Average 25.2% through

21 Other StationsAverage 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

9014 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3827 0 0 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 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

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 NetworkMaster 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 time-

of-day Level of Service Peak 15 minute speeds and flow

densities VOC, CO, NOx Emissions

Network Editing Tools

Scenario ToolsList ScenariosAdd ScenarioDelete ScenarioCopy Projects

Network Editing Tools

Signal ToolsUpdate Signal FieldsAdd SignalsDelete 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)

75 72.5 70 67.5 65 62.5 60 57.5 556 f

t 3 f

t 0 f

t0.92

0.93

0.94

0.95

0.96

0.97

0.98

0.99

1.00

adjustment factor

free-flow speed

lateral clear-ance

Capacity Reduction Factor for Lateral Clearance

Speed & Capacity Estimation

Signal Impedance

HCM 2000 procedure

Delay/veh = uniform delay * PF + incremental delay + initial queue delay

where, PF = progression factor = f (arrival type, g/C)

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.

Cgcv

CgC

,1min1

15.0 2

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 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 Production Model

Trip Generation (Cont’d)

Trip Purpose

Independent Variable

ParameterTrip

PurposeIndependent

VariableParameter

HBW Total Employment 0.5085

NHBO

Households 3.8321HBS K-12 Enrollment 1.7211 Retail Employment 1.5399HBU University Enrollment 1.1488 Office Employment 0.6419

HBO

Population 0.6778 Gov’t. Employment 0.3106Retail Employment 2.6391

Trucks

Labor Employment 1.5730

Office Employment 0.3638Industrial

Employment1.2840

Gov’t. Employment 0.6607 Retail Employment 1.2060

NHBW (Other)

Population 0.1758 Office Employment 0.5140

Retail Employment 0.6084 Auto Ex/In

Total Employment^0.5

22.8865

Office Employment 0.1244 Households 0.2752Gov’t. Employment 0.1179 NHBW

(Work)Total Employment 0.3567

Other Employment 0.1171

Trip Attraction Model

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-to-county flows and other important interactions

Trip Distribution (Cont’d)Friction Factor Calibration for Home-Based Work

0.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

8.00

Time

Tri

p L

eng

th F

req

uen

cy D

istr

ibu

tio

n

BTLFD TLFD#5 TLFD#10 TLFD#15

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 production-attraction format to origin-destination tables

Directional factors by trip purpose and by TOD

Time of Day (Cont’d)

Trips by Purpose by Hour

0

10000

20000

30000

40000

50000

60000

70000

80000

90000

HBW

HBK12

HBU

HBO

NHBW

NHBO

EI

EE

TRK

Time of Day (Cont’d)

AM PM OFF DAILY AM PM OFF DAILYHBW 27.5% 29.1% 43.4% 100.0% NHO 8.7% 24.8% 66.6% 100.0%

p-a 26.6% 2.9% 23.1% 52.6% p-a 4.3% 12.4% 33.3% 50.0%a-p 0.9% 26.2% 20.3% 47.4% a-p 4.3% 12.4% 33.3% 50.0%

HBS 49.2% 30.0% 20.8% 100.0% EI 7.8% 20.8% 71.4% 100.0%p-a 49.2% 0.6% 4.7% 54.5% p-a 1.8% 12.9% 35.0% 49.8%a-p 0.0% 29.4% 16.1% 45.5% a-p 6.0% 7.8% 36.4% 50.2%

HBU 29.8% 19.6% 50.5% 100.0% EE 7.8% 20.8% 71.4% 100.0%p-a 29.8% 2.5% 22.5% 54.9% p-a 3.9% 10.4% 35.7% 50.0%a-p 0.0% 17.1% 28.0% 45.1% a-p 3.9% 10.4% 35.7% 50.0%

HBO 14.7% 25.4% 60.0% 100.0% TRK 11.0% 15.0% 74.0% 100.0%p-a 11.8% 9.6% 26.7% 48.2% p-a 5.5% 7.5% 37.0% 50.0%a-p 2.8% 15.8% 33.2% 51.8% a-p 5.5% 7.5% 37.0% 50.0%

NHW 16.0% 25.7% 58.3% 100.0%p-a 2.2% 21.5% 31.3% 55.0% ALL 15.9% 25.3% 58.8% 100.0%a-p 13.9% 4.2% 26.9% 45.0%

Time of Day & Directional Factors

Mode Share

Private Auto Mode Share by Purpose (from HH Survey)

Mode ShareHBW 98%HBS 73%HBU 78%HBO 98%NHBW 98%NHBO 96%

Vehicle Occupancy

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

Vehicle Occupancy by Purpose by Time of Day (from HH Survey)

Traffic Assignment Time-of-day assignments (i.e., separate AM-peak, PM-peak & Off-

peak assignments)

Directional flows by time-of-day

User equilibrium assignment by mode with trucks preloaded

Calibrated volume-delay functions by functional class and signalization

Volume Delay Parameters Roadway Class

Alpha Beta Rural Interstate 8.0 4.5 Urban Interstate 0.40 2.7 Other Freeways 0.83 2.7

Signalized Unsignalized Alpha Beta Alpha Beta

Rural Principal Arterials 0.7 6.0 2.0 6.0 Urban Minor Arterials 1.8 7.0 5.5 7.0

Rural Collectors 8.0 4.5 14.0 4.5 Other 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 Under-reporting Factor Home-Based Work 1.22 Home-Based School 1.41

Home-Based University 1.41 Home-Based Other 1.60

Non-Home Based Work 2.32 Non-Home Based Other 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 external-internal trip productions to HBW & HBO attractions

Resolution of Calibration IssuesIssue: Over-Loading High Class Facilities &

Under-Loading Low Class Facilities

Solution: Calibrated Volume-Delay Function Parameters

Knoxville Regional-Volume Delay Curves

0.00

0.20

0.40

0.60

0.80

1.00

1.20

0.00 0.50 1.00 1.50 2.00 2.50

V/C

Sp

ee

d D

ec

ay

8.0/4.5

.40/2.7

.83/2.7

0.7/6.0

1.8/7.0

8.0/4.5

3.0/6.0

2.0/6.0

5.5/7.0

14/4.5

12/6.0

Resolution of Calibration IssuesIssue: 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

Volume Range Average Counts Average Loading % RMSE % Error % Threshold VMT %

Error 1,001 ~ 2,000 1,476 2,442 153.38 65.45 100 46.05 2,001 ~ 3,000 2,461 3,357 101.28 36.39 100 29.05

3,001 ~ 4,000 3,448 3,586 71.34 4.01 50 0.13 4,001 ~ 5,000 4,483 4,887 69.35 9.02 50 2.60 5,001 ~ 6,000 5,461 5,835 49.52 6.85 25 4.28

6,001 ~ 8,000 7,033 7,040 45.94 0.10 25 -1.75 8,001 ~ 10,000 8,910 8,618 44.78 -3.28 25 -0.31 10,001 ~ 15,000 12,107 11,061 33.08 -8.63 20 -8.63

15,001 ~ 20,000 17,349 15,230 25.54 -12.22 20 -9.11 20,001 ~ 25,000 22,361 20,357 21.86 -8.96 20 -4.82 25,001 ~ 30,000 27,633 26,419 17.84 -4.39 15 -2.12

30,001 ~ 40,000 33,890 33,025 13.51 -2.55 15 -1.34 40,001 ~ 50,000 43,730 42,801 11.16 -2.12 15 1.16 50,001 ~ 60,000 57,730 59,847 17.53 3.67 10 3.29

> 60,000 66,828 70,221 8.01 5.08 10 2.58

ALL 11,531 11,337 31.96 -1.68 -0.15

Model Performance by Volume Group

Final Validation Results

Model Performance by Functional Class

Functional Classification Average Counts Average Loading % RMSE % Error VMT %

Error Rural Interstate 44,246 45,928 11.51 3.80 2.95

Rural Prin. Arterial 16,395 16,497 21.61 0.63 1.14 Rural Minor Arterial 9,352 9,720 30.07 3.94 6.74

Rural Major Collector 4,322 4,941 63.44 14.31 14.32 Rural Minor Collector 3,545 3,821 70.60 7.78 1.73

Rural Local Roads 3,075 2,914 89.45 -5.21 -24.74 Urban Interstate 39,960 41,884 9.84 4.82 4.51

Urban Prin. Arterial 23,240 21,844 21.47 -6.01 -4.96 Urban Minor Arterial 10,336 9,458 41.53 -8.50 -10.10

Urban Collectors 7,123 6,360 54.65 -10.71 -10.87 Urban Local Roads 4,348 3,843 68.50 -11.61 -12.98

All 11,531 11,337 31.96 -1.68 -0.15

Final Validation Results

Model Performance by Major Corridor

Corridor Average Counts Average Loading % RMSE % Error VMT % Error I-40 48,552 51,729 11.47 6.54 4.56 I-75 44,374 44,199 10.06 -0.39 1.82

I-275 28,023 31,200 12.62 11.34 12.39 I-640 25,645 25,473 12.63 -0.67 0.98 I-81 36,804 38,708 7.37 5.17 4.47

I-140 18,365 18,509 9.77 0.79 -1.97 Chapman Hwy 24,608 24,978 21.14 1.51 5.66

US129 37,999 33,540 18.29 -11.73 -12.20 SR66/US321 34,303 34,731 8.97 1.25 2.54

Pellissippi Pkwy 16,588 18,330 20.50 10.50 3.81 SR62 22,616 19,474 20.03 -13.89 -13.12

Final Validation Results

Model Performance by Screenline, Area Type, & County

Category Avg Counts Avg Loading % RMSE % Error VMT %

Error Knox County Line 15,530 15,388 20.54 -0.91 0.62

Blount County Line 10,350 10,325 25.17 -0.24 -25.63 Knox & Blount C.L. 12,013 11,626 28.45 -3.23 -11.97

Screen-line

Knox-Blount Border 18,643 19,341 6.64 3.74 2.08 Major Employment District 13,469 12,632 36.05 -6.21 -5.91

Urban Areas 11,648 10,807 33.13 -7.22 -5.82 Suburban Areas 14,019 13,934 29.20 -0.61 -0.99

Area Type

Rural Areas 10,442 11,020 29.36 5.54 5.33 Knox County 11,679 11,106 33.08 -4.90 -3.72

County Blount County 9,597 8,678 42.76 -9.57 -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

525 55.39 0.46132851 29232 2926 2401 227 7.7User Corridor #10 9.44 162084

14624User Corridor #9 21.55 745212 672106 73106 16134 1510 46.19 0.46

2227 45.01 0.642284 20.9

1154 7.2

391498 100619 10934 8707User Corridor #8 15.72 492116

10827User Corridor #7 22.13 531549 492551 38998 11666 839 45.56 0.5

637 62.98 0.5440 7.9

1396 12.0

324035 40292 5785 5148User Corridor #6 21.56 364327

3471User Corridor #5 7.73 297384 213151 84233 4842 1371 61.42 0.5

1569 59.88 0.5931 10.9

265 6.0

417142 93946 8536 6967User Corridor #4 20.17 511088

2212User Corridor #3 4.79 141908 124408 17500 2523 311 56.24 0.82

10623 53.85 0.582507 7.8

412 16.3

1447251 574878 37548 26925User Corridor #2 52.76 2022129

72089User Corridor #1 113.55 5558630 4027241 1531389 99570 55.83 0.72

TRUCK_VHTAVGSPEED VC

9808 11.0

DELAYPTCTRUCK_VMTVHT AUTO_VHT

27481

CLASS MILES VMT AUTO_VMT

Traffic statistics by functional class, area type, county, and corridor - including user-defined corridors:

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 Regionfrom MOBILE6 and the Knoxville Regional Travel Demand ModelMon Mar 29 02:08:59 2004

Year: 2000Scenario: TestAQ 12748220 VMT in Knox County VOC CO NOxScenario: 29.26 tons/day 326.91 tons/day 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 aquarter mile of theroute

THANK YOU!