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Knoxville Regional Travel Demand Model Upgrade Program May 6, 2004 Knoxville Regional Travel Demand Model Upgrade Program May 6, 2004.

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Presentation on theme: "Knoxville Regional Travel Demand Model Upgrade Program May 6, 2004 Knoxville Regional Travel Demand Model Upgrade Program May 6, 2004."— Presentation transcript:

1 Knoxville Regional Travel Demand Model Upgrade Program May 6, 2004 Knoxville Regional Travel Demand Model Upgrade Program May 6, 2004

2 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

3 Expanded Study Area

4 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-12 th grade enrollments

5 External Trips  30 External Stations  34,000 daily trips  Five Interstates  Average 25.2% through  21 Other Stations  Average 1.2% through

6 External Trips (Cont’d)

7 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

8 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

9 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

10 Network Editing Tools Scenario Tools  List Scenarios  Add Scenario  Delete Scenario  Copy Projects

11 Network Editing Tools Signal Tools  Update Signal Fields  Add Signals  Delete Signals  Import Signals from GIS Layer

12 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)

13 Speed & Capacity Estimation

14 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.

15 Model Interface

16 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

17 Trip Generation (Cont’d) Trip Purpose1 st Predictor2 nd PredictorTrip Rate HBWWorkers/H.H.Vehicles/H.H.1.21 HBSStudents/H.H.None0.61 HBUUniversity Student/TAZ None0.15 HBOHousehold SizeVehicles/H.H.3.49 NHBWWorkers/H.H.Household Income0.80 NHBOHousehold SizeVehicles/H.H.1.87 Total7.42 Trip Production Model

18 Trip Generation (Cont’d) Trip Purpose Independent Variable Parameter Trip Purpose Independent Variable Parameter HBWTotal Employment0.5085 NHBO Households3.8321 HBSK-12 Enrollment1.7211Retail Employment1.5399 HBUUniversity Enrollment1.1488Office Employment0.6419 HBO Population0.6778Gov’t. Employment0.3106 Retail Employment2.6391 Trucks Labor Employment1.5730 Office Employment0.3638Industrial Employment1.2840 Gov’t. Employment0.6607Retail Employment1.2060 NHBW (Other) Population0.1758Office Employment0.5140 Retail Employment0.6084 Auto Ex/In Total Employment^0.522.8865 Office Employment0.1244Households0.2752 Gov’t. Employment0.1179 NHBW (Work) Total Employment0.3567 Other Employment0.1171 Trip Attraction Model

19 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

20 Trip Distribution (Cont’d)

21 Feedback Loop for the Knoxville Model

22 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

23 Time of Day (Cont’d)

24 Time of Day & Directional Factors

25 Mode Share Private Auto Mode Share by Purpose (from HH Survey)

26 Vehicle Occupancy AMPMOFF HBW 1.091.101.08 HBS 2.582.402.25 HBU 1.22 HBO 1.991.881.77 NHBW 1.091.161.20 NHBO 1.971.881.71 Vehicle Occupancy by Purpose by Time of Day (from HH Survey)

27 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

28 Traffic Assignment (Cont’d) Final Validated Assignment

29 Resolution of Calibration Issues Issue:Global Under-Loading Solution: ODOT Factors for Trip Under-reporting - from GPS validation of household travel surveys

30 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)

31 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

32 Resolution of Calibration Issues Issue:Over-Loading High Class Facilities & Under-Loading Low Class Facilities Solution: Calibrated Volume-Delay Function Parameters

33 Resolution of Calibration Issues Issue:Unbalanced Interactions between Area Types and with External Stations Solution: Socioeconomic (K) Factors Average K Factors

34 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%

35 Final Validation Results Model Performance by Volume Group

36 Final Validation Results Model Performance by Functional Class

37 Final Validation Results Model Performance by Major Corridor

38 Final Validation Results Model Performance by Screenline, Area Type, & County

39 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

40 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

41 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

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

43 AQ_PLuS: Link Emissions Link-Specific Emissions  Volatile Organic Compounds  Carbon Monoxide  Oxides of Nitrogen in grams/day

44 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 VOC CO NOx Scenario: 29.26 tons/day 326.91 tons/day 45.31 tons/day

45 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

46 THANK YOU!


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