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Ed Hard Stephen Farnsworth David Pearson

Methods for Conducting O-D Travel Surveys on High Volume (HV) Facilities. Ed Hard Stephen Farnsworth David Pearson. 11 th Conference on Transportation Planning Applications May 7, 2007. Problem: Collecting Survey Data on High Volume Facilities.

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Ed Hard Stephen Farnsworth David Pearson

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  1. Methods for Conducting O-D Travel Surveys on High Volume (HV) Facilities Ed Hard Stephen Farnsworth David Pearson 11th Conference on Transportation Planning Applications May 7, 2007

  2. Problem: Collecting Survey Data on High Volume Facilities The inability to conduct ‘intercept’ travel surveys on high volume facilities means loss of key data needed for local planning and travel models.

  3. External Surveys and HV Sites • Conducted around periphery of urban areas • HV sites carry majority of traffic into/out of area • Example: 2005 Dallas Survey • 93 external stations • 9 of 93 were HV • 9 HV sites carried 52% of traffic

  4. Traditional Intercept Method Computer Tablets Traffic Control Plans

  5. License Capture Methods • Match or Mailout • Plates recorded by • Video camcorders • High-speed cameras • Voice recorders • Manually with ‘observers’ and ‘recorders’

  6. Categories of HV Survey Methods • Intercept Interview • Intercept Postcard Mailback • License Match • License Mailout

  7. Data Elements Collected Intercept vs. License Methods

  8. Select Example Across US

  9. Factors Considered in Selecting HV Method • Roadway cross-section, physical conditions • Policies of DOT, affected agencies • Level of traffic (AADT) • Data elements and quality • Costs and resources available • Potential for negative feedback

  10. Intercept Interview Method • Limited use in HV externals. • Used more in toll feasibility, user / attitudinal studies • Use along HV facilities: • At / near ramps or tolls • On shoulders along interstate (one case) • At weigh stations, rest areas, truck stops for commercial vehicles / trucks • External Surveys: Philadelphia (2001) Phoenix (1999), Denver (1998)

  11. Intercept Interview

  12. Intercept Postcard Mailback Method • Postcard handout in lieu of interview • Limited use in externals, more in corridor or user / attitudinal studies • Used on / near freeway ramps, toll plazas • 2002 Chattanoonga, TN external

  13. Intercept Postcard Mailback

  14. Video License Capture • High-speed, specification camcorders used • Rear license plates recorded • Info needed: plate #, state, time, direction • Camera’s on overpass or shoulder • Used in majority of match / mailout surveys

  15. License Match Method • Plates matched between HV sites • All HV sites recorded on same day • Used to estimate percent I-E and E-E trips (local vs. thru movements) • Travel time runs needed

  16. License Match

  17. Surveys Using License Match • 2006 San Antonio / Austin External • 8 HV sites requiring 34 video cameras • 42 intercept sites • 2006 Dallas-Ft. Worth External • 9 HV sites requiring 36 video cameras • 34 intercept sites • 2001 Metrolina Region External • 43 video cameras

  18. License Mailout Method • Most common method for HV sites in externals • Same as ‘match,’ but plates queried against state DMV records and surveys mailed • Used for non-commercial vehicles only • Mailout includes info on survey purpose, assurance for anonymity, toll free #, etc.

  19. License Mailout

  20. What Traffic Level is High Volume? • Few agencies have HV ‘threshold’ value • Intercepts on freeways, interstates often prohibited • Queuing analyses used to determine volume when queuing is problematic. Two categories: • Blocked traffic lane, 2-lane roadways • Lane reduction, 2 or more lanes in survey direction

  21. Queuing Analysis: Blocked Lane • 2 lane roadways • Queues correlated with traffic volume • Number of surveyors has little affect • For TxDOT, 150-200+ veh / hour per lane problematic

  22. Queuing Analysis: Lane Reduction • 2 or more lanes in direction of survey • TCP lane reductions • Queues problematic as volumes approach 1,000 vph • Analysis supports TxDOT policy defining 20,000 ADT as HV

  23. Technology in HV Surveys • Current • Video / camcorders, hi-speed cameras • Infrared video • Optical character recognition (OCR) • Video data reduction software • Radio frequency ID, Toll / E-Z tags • Future potential • Cellular phone trackage • Vehicle telematics

  24. License Mailout: TxDOT Practice Message boards used to inform public

  25. License Mailout: TxDOT Practice Set-up on IH-10 at Texas / Louisiana border March 2007

  26. License Mailout: Lessons Learned • Keep survey form simple • Cover letter: content, tone, and appearance important • Use pre-addressed, postage paid envelope or postcard • Ensure return responses are anonymous • Provide toll free number • Keep accurate records of all calls received • No more than 3-day turn-around between capture and mailout

  27. QUESTIONS Ed Hard (979) 845-8539 e-hard@tamu.edu

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