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Field Practices in External Survey Data Collection Presented by: J.D. Allen, AICP

Today's Presentation. Data Collection PurposeMethodsPros and ConsExamplesData UsabilityDetermining Factors for Method SelectionData ExpansionLessons Learned. Data Collection Purpose. External Station or Corridor Origin/Destination Surveys are conducted to determine the number and characteri

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Field Practices in External Survey Data Collection Presented by: J.D. Allen, AICP

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    2. Today’s Presentation Data Collection Purpose Methods Pros and Cons Examples Data Usability Determining Factors for Method Selection Data Expansion Lessons Learned

    3. Data Collection Purpose External Station or Corridor Origin/Destination Surveys are conducted to determine the number and characteristic of the trips traveling through a study area (or along a corridor) Usually collected to provide better inputs to the travel demand model External – External (EE) trips are unique to an area Conducted around the periphery of a study area or at various locations along a corridor

    4. Methods Intercept Interviews Postcard Handout / Mail Back Video License Plate Capture Matching Mail Out / Mail Back Follow up call

    5. Methods – Intercept Interviews Used mainly on lower volume facilities (<20K ADT) Use along high volume facilities: At/near ramps or tolls sites Weigh station – commercial vehicles Rest areas Effective for toll feasibility, user/attitudinal studies Electronic collection Tablet PC Handheld device Paper collection Traffic control necessary

    6. Methods – Intercept Interviews

    7. Methods – Intercept Interviews

    8. Methods – Intercept Postcards Postcards are handed out and mailed back Used mainly on lower volume facilities (<20K ADT) for stand alone external station collection Traffic control necessary Used along higher volume facilities at alternate locations Rest areas Convenience stores/gas stations Visitor Centers Effectively used at intersection locations Minimal traffic control necessary Signal timing a consideration

    9. Methods – Intercept Postcards

    10. Methods – VLP Capture Passive data collection method Effective for use on high volume sites Video camcorders or digital cameras used depending on lighting conditions Rear license plate captured Cameras placed on shoulders or overpass Data elements include: license, state, vehicle classification, time, direction Plate matching for through trips DMV matching for follow up survey or home location

    11. Methods – VLP Matching Plates captured at all locations on same day Plates transcribed (92-95% from OCR and manual) 50% good transcription with OCR 30% with OCR & manual correction 12-15% manual transcription 2-3% obscured 2-3% missing (daylight conditions) State and vehicle class entered manually Matching results in site to site occurrence matrix EE trip % by site

    12. Methods – VLP Capture

    13. Methods – VLP Capture Follow Up Plates captured at all locations on same day or on different days Plates transcribed usually with OCR only Match with DMV records for follow up Call interview Mail out/mail back postcard Call interview can be anonymous or not Mail out survey can ask questions much like postcard handout

    14. Methods – VLP Capture Follow Up

    15. Methods – VLP Capture Setup

    16. Methods – VLP Capture Setup

    17. Methods – VLP Capture Examples

    18. Methods – VLP Capture Examples 2005 Baton Rouge – 3 VLP, 9 postcard* 2005 DFW – 9 VLP, 38 interviews, 18 comm. interview 2005 San Antonio (1604) – 3 VLP, 10 postcard 2005 Washoe County (Reno) – 7 VLP 2007 Baltimore – 9 VLP on 3 corridors 2007 Kansas City – 6 VLP, call follow up 2007 Treasure Valley – 9 VLP, 3 interview (POIs), alt. sites 2008 Delaware (US 301) – 7 VLP 2008 MAG/PAG – 18 VLP 2010 PART, NC – 7 VLP, 13 interviews 2010 Colorado Front Range – 11 VLP, 47 postcard

    19. Data Usability

    20. Method Selection Facility types (interstate, arterial…) Roadway cross-section, physical conditions Policies of DOT and other affected agencies Volume of traffic (> or < 20k ADT) Data elements and quality Costs and resources available Time of year (lighting) Sensitivity to potential negative public reaction

    21. Data Expansion Data reduction Develop expanded EE trip tables from VLP Develop expanded EE/IE trip tables from other data Aggregate intercept and VLP EE/EI trip tables Assign proxy EE/EI trip distributions to non-surveyed sites Develop final EE/EI trip tables

    22. Lessons Learned Intercept interview Best done on low volume facilities (queuing) Becoming less popular Intercept postcard Self selection bias may be acceptable trade off Best done at intersections and alternate locations VLP capture Passive method: no interruption for traveling public Best done without press involvement Mail out/mail back survey from VLP Need quick turn around for mail out Keep survey form simple Provide website for participation and toll free contact number

    23. Questions J.D. Allen, AICP jdallen@emailatg.com 337.310.7020 office 337.802.6655 mobile www.alliance-transportation.com

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