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FSUTMS-Cube Calibration Standards

FSUTMS-Cube Calibration Standards. Transportation leadership you can trust. Draft Guidelines and Standards. presented to Florida Model Task Force Model Advancement Committee presented by Robert G. Schiffer, AICP Thomas F. Rossi Cambridge Systematics, Inc. Yongqiang Wu, P.E.

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FSUTMS-Cube Calibration Standards

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  1. FSUTMS-Cube Calibration Standards Transportation leadership you can trust. Draft Guidelines and Standards presented toFlorida Model Task Force Model Advancement Committee presented byRobert G. Schiffer, AICP Thomas F. RossiCambridge Systematics, Inc. Yongqiang Wu, P.E. Florida Department of Transportation November 28, 2007

  2. Presentation Overview • Literature Review • Default Guidelines and Standards(LRTP transit models) • Checking Input Data • Trip Generation • Trip Distribution • Mode Choice • Trip Assignment • Validation for Other Model Applications • Discussion on Volume-over-Count Ratios • Next Steps

  3. Project Overview • Follow-up to Phase I Study on model parameters • Prepared summary of NHTS statistics for potential model use • Identified adjustable parameters and potential sourcesfor defaults • Final report is available at the FSUTMSOnline web site • http://www.fsutmsonline.net/images/uploads/mtf-files/FSUTMS-Cube_Parameters.pdf • Phase II Study on calibration standards includes 4 subtasks • Literature Review (complete) • Model Calibration/Validation Guidelines and Standards (today) • Best Practices for Model Calibration/Validation (next) • Documentation – 1) Calibration and Validation Standards;2) Best Practices for Model Validation; 3) Guidelines forModel Application

  4. Project Overview (continued) • Calibration vs. validation • Calibration – process where models are adjusted to simulateor match observed travel behavior in the study area • Validation – procedure used to adjust models to simulatebase-year traffic counts and transit ridership figures • Standards vs. guidelines/benchmarks • Standards – desirable accuracy levels for comparing estimated versus observed metrics • Benchmarks – documented statistical ranges from literature review, model outputs, NHTS, etc. • Literature review • 60+ documents reviewed – specific modelsand reference reports

  5. Default Guidelines and StandardsChecking Input Data • Socioeconomic data • Visual comparisons • Statistical comparisons • Regionwide comparisons(below) • Persons perDU (or HH) • Employment/population ratio • Autos/DU (or HH)

  6. Default Guidelines and StandardsChecking Input Data (continued) • Highway network data • Transit network data • Highway and transit speed data • Hierarchy • Balance highway and transit • Terminal times • Hierarchy • Phase I Report

  7. Default Guidelines and StandardsTrip Generation • Aggregate trip rates • Person trips/TAZ • Person trips/person • Person trips/DU (or HH) • HBW person trips/employee • Total unbalanced attractions versus productions by purpose • Preferred +/-10%; acceptable in some instances +/-50% • Percent external-external trips by zone/station • Great variation expected (4-21 percent range documented) a Generally excludes nonmotorized trips; including motorized trips could increase person trips per DU up to 11.5.

  8. Default Guidelines and StandardsTrip Generation (continued) • Percent trips by purpose a HBO includes a variety of special trip purposes depending on the model (e.g., airport, college, and shop). b HBNW accounts for all home-based trip purposes except HBW. c NHB includes combined purposes for NHB Work and NHB Nonwork, where appropriate.

  9. Default Guidelines and StandardsTrip Distribution • Average trip length by purpose • Trip length frequency distributions by purpose • Coincidence ratios by purpose – measures the percent of areathat coincides for two triplength frequencies Percent of Total Trips 8% a HBO includes a variety of special trip purposes, depending on the model (e.g., airport, college, and school). b NHB includes combined purposes for NHB Work and NHB Nonwork, where appropriate. c Some lower coincidence ratios have been deemed acceptable for trip purposes that had relatively few trips and therefore higher error rates. Coincidence Ratio = 0.82 Estimated (ATL = 18.2 Min) 6% Observed (ATL = 18.9 Min) 4% 2% 0% 0 10 20 30 40 50 60 Travel Time (in Minutes)

  10. Default Guidelines and StandardsTrip Distribution (continued) • Percent intrazonal trips by purpose • Node-point charts • Zone-based • Number of trips • Trip productions/attractionsby purpose a HBO includes a variety of special trip purposes, depending on the model (e.g., airport, college, and school). b NHB includes combined purposes for NHB Work and NHB Nonwork, where appropriate.

  11. Default Guidelines and StandardsMode Choice • Mode split targets (ideal) • Trip purpose • Mode • Auto ownership level • Geographic subarea

  12. Default Guidelines and StandardsMode Choice (continued) • Mode splits by observed calibration targets • Total area transit trips, estimatedversus observed • Transit trips between districts • Tabular comparisons (CTPP) • Desire lines • Mean trip length, estimated transit trips versus observed

  13. Default Guidelines and StandardsTrip Assignment • Volume-over-count ratios • +/-1 lane percent error (recalculated per FDOT LOS Handbook) • Aggregate VMT • VMT/HH (60-75) • VMT/person (24-32) • VMT/commercial vehicle (3-25%)

  14. Default Guidelines and StandardsTrip Assignment (continued) • Screenline volume-over-count • RMSE by volume group • Transit assignment validation

  15. Other Model ApplicationsLRTP Highway Only Models • Same default guidelines and standards except • Replace mode choice checks with auto occupancy comparisons against NHTS and other surveys • Commercial vehicle VMT checks not likely relevant • No transit assignment validation a HBO includes a variety of special trip purposes, depending on the model (e.g., airport, college, and school). b NHB includes combined purposes for NHB Work and NHB Non-Work, where appropriate.

  16. Other Model ApplicationsFTA New Starts Models • Transit networks and pathbuilding checks • Compare skim settingsto on-board surveys • Trip distribution checks • Mode choice calibration • Highway assignment checks • Transit assignment checks • Assign on-board survey trip table and compare ridership • SUMMIT diagnostics * FTA published guideline.

  17. Other Model Applications Subarea Models • Prerequisite – approved regional model validation • Input data – focus on socioeconomic and network data • Trip generation – review and compare subarea versus regional model aggregate trip rates • Trip distribution – compare subarea versus regional average trip length and percent intrazonal trips by purpose • Mode choice – check subarea mode shares versus regional • Trip assignment – volume-over-count (v-o-c), percent error, VMT and VHT v-o-c, v-o-c by screenline/cutline, and RMSE

  18. Other Model Applications Corridor Models • Same subarea modelvalidation checks • Input data – focus on network details surrounding corridor • Trip generation – review corridor productions and attractions by zone • Trip distribution –desire line analyses • Mode choice – review of mode shares within study area • Trip assignment – more stringent standards for v-o-c, v-o-c by screenline/cutline

  19. Other Model Applications Models for DRIs and Other Impact Studies • Input data • SE data – site, nearby zone assumptions, pop/TAZ • Networks – verify coding, path traces from site • Transit – access coding, headways, stop locations near site • Trip generation – document trip rate assumptions • Trip distribution – district summaries • Mode choice – check ITE tripsversus model trips • Trip assignment – select zoneand select link, turn volumes

  20. An Issue for the MTF to Discuss… Discussion on volume-over-count ratios • Ratio of summed modeled volumes for group of linksand the sum of count volumes on the links(should be near 1.0) • This check does appear in the draft report at this time • In the opinion of some, this is mathematically erroneous because of double counting • It is somewhat duplicative of VMT checks

  21. An Example V = 7,500 V = 7,500 v/c = (7,500+7,500+5,000)/(5,000+5,000+5,000) = 1.33 C = 5,000 C = 5,000 V = 5,000 C = 5,000 1 mile

  22. An Example (continued) V = 5,000 V = 5,000 v/c = (5,000+5,000+7,500)/(5,000+5,000+5,000) = 1.17 C = 5,000 C = 5,000 V = 7,500 C = 5,000 1 mile

  23. Proposed Solution • Use VMT check • Example has same solution for both cases VMT(m) / VMT(c) = 1.25 • VMT is not double counted • Screenline/cutline checks should be retained since double counting should not be an issue

  24. Next Steps • Take comments from MTF committee today • Revise draft guidelines and standards based on FDOT and MTF committee comments • Prepare technical report on best practices • Develop guidelines for model application work

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