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

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

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

Traditional Intercept Method Computer Tablets Traffic Control Plans

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

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

Data Elements Collected Intercept vs. License Methods Data Element Intercept License Match Licens out Local vs. Thru Trip O&D X ResidencyX Veh. Occupancy X Trip Purpose X Trip Length X Trip Frequency X

Select Example Across US External Survey HV Survey Method Used 1. Texas DOT License Mailout and License Match License Mailout and License Match 2. Tampa, FL License Mailout License Mailout 3. Denver, CO Intercepts on Freeway Off Ramps Intercepts on Freeway Off Ramps 4. Philadelphia, PA Intercepts on Shoulders of Freeway Intercepts on Shoulders of Freeway 5. Ohio, DOT License Mailout and Intercepts License Mailout and Intercepts 6. Phoenix, AZ Intercepts at Ramps/Interchanges Intercepts at Ramps/Interchanges 7. Los Angeles, CA License Mailout License Mailout 8. Raleigh, NC License Match, Rest Area Intercepts License Match, Rest Area Intercepts 9. Little Rock, AR License Mailout License Mailout 10. Chattanooga, TN Mailback at Ramps / Interchanges Mailback at Ramps / Interchanges

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

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

Intercept Interview PROsCONs Data quality Data quality Response rate Response rate All data elements All data elements collected collected Control of sampling Control of sampling Ability to follow-up Ability to follow-up Data available sooner Data available sooner Safety Safety Stopping vehicles Stopping vehicles Agency coordination Agency coordination TCP and permit TCP and permit approvals approvals Dependent on law Dependent on law enforcement enforcement Negative press / PR Negative press / PR

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

Intercept Postcard Mailback PROsCONs Less disruption Less disruption Traffic delays shorter Traffic delays shorter Most data elements Most data elements collected collected Cost < intercept Cost < intercept Safety Safety Stopping vehicles Stopping vehicles Self selection bias Self selection bias Lower response rate Lower response rate TCP and permit TCP and permit approvals approvals Dependent on law Dependent on law enforcement enforcement

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

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

License Match PROsCONs Safety Safety No traffic disruption No traffic disruption No TCP required No TCP required No use of state DMV No use of state DMV records records Limited data Limited data All sites must be All sites must be recorded on same recorded on same day day

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

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

License Mailout PROsCONs Safety Safety No traffic delay or No traffic delay or disruption disruption No TCP required No TCP required Most data elements Most data elements collected collected Data quality Data quality Use of DMV records Use of DMV records Quick turn-around Quick turn-around needed between needed between capture and mailout capture and mailout Out-of-state plates Out-of-state plates Negative PR, privacy Negative PR, privacy rights rights

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

Queuing Analysis: Blocked Lane Queuing Analysis: Blocked Lane 2 lane roadways 2 lane roadways Queues correlated with traffic volume Queues correlated with traffic volume Number of surveyors has little affect Number of surveyors has little affect For TxDOT, veh / hour per lane problematic For TxDOT, veh / hour per lane problematic

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

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

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

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

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

QUESTIONS Ed Hard (979)