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Travel Behavior Panel Surveys: Measuring the Impacts of Road Pricing in Seattle and Atlanta

Travel Survey Methods Committee MeetingJanuary 25, 2012

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Project Background

• USDOT Urban Partnership Agreement (UPA)/Congestion Reduction Demonstration (CRD) programs fund selected cities/ regions to implement a comprehensive, integrated approach to reducing congestion– The four T’s: Tolling; Transit;

Technology; Telecommuting

– Recipients: Atlanta, Seattle, Miami, Minneapolis, Los Angeles, San Francisco

• National Evaluation being conducted by Battelle

• FHWA funds Volpe Center to perform household panel survey

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Source: Wikipedia

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Seattle and Atlanta

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Evaluation Questions

How did travel times, vehicle miles traveled, and daily travel budgets change at the individual/household level?

Were there shifts in departure times or modes? In origin-destination patterns?

For those who used the priced facility less, where did the reduced trips go? Telework? Combined errands? Route diversion?Atlanta: How do 2-person carpools adapt to the new occupancy requirements?

What are the equity impacts of the road pricing policies?

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Overall Study Approach

• Household Panel Study: same households before and after road pricing

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Overview of Study Population

• Peak hour corridor drivers: sample through license plate capture with match to registered address

• Seattle: SR-520 and I-90• Atlanta: I-85 and Buford Highway

• Peak hour corridor transit users: In-person intercept • Seattle: bus stops, transit centers; park & rides; on-board

buses• Atlanta: park & rides in corridor: MARTA stations

• Corridor vanpool members: send email to vanpool participants

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Atlanta Sample Development (Drivers)

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Sample Development for Transit/Vanpools

• Seattle: in-person intercept October 18-21, 2010– on-board intercept (ipad) on buses crossing Lake Washington – Postcard handout: Redmond and Bellevue Transit Centers;

South Kirkland and Eastgate Park & Rides; on-board buses; downtown bus stops

• Atlanta: in-person intercept March 21-25, 2011– Postcard handout only: Discover Mills, Indian Trail, Mall of

Georgia, and I-985 Park and Rides, Doraville and Lindbergh MARTA Stations

• Vanpool recruitment: Georgia Regional Transportation Authority/King County sent an e-mail to registered vanpoolers who use the corridor inviting them to participate (~500)

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Survey Materials

• Memory Jogger• Reminder postcards and

emails

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Online survey tool• Household survey on demographics (completed by one person)• 2-day travel diary completed by all adult (18+) household members• Additional survey questions: typical commute behavior; typical use

of the facility; trip satisfaction; attitudes and values• Phone option available; Spanish version of materials in Atlanta

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Pilot Study• Purpose: Test all steps of survey administration

– Recruitment method (license plate capture and transit intercept; effectiveness of materials; incentive structure)

– Online tool: questionnaire design and functionality, survey duration

– Obtain estimate of response rate

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Modal Segment

SeattleResponse Rate

Atlanta Response Rate

Auto 9.6% (N=175) 8.9% (N=176)

Transit 18.3% (N=119) 14.7% (N=49)

294 households 225 households

NOTE: “Completion” defined as all adult members of the household complete their travel diary

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Pilot Study, continued

• Findings: Overall, no major issues or problems– Cut survey questions due to comments on length – Clarify several error messages/instructions – Add response categories for some questions

• Trip purpose: “exercise/gym”

– Increase automation• Pre-populate starting point for day 2 trip roster with ending point

from day 1

– Utilize $15 gift card incentive (resulted in 9.4% response) • $10 gift card: 7.0% response rate• $10 gift card with enclosed $1 bill: 9.8% response rate• $15 gift card with enclosed $1 bill: 11.8% response rate

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Incentives and Panel Maintenance

• Each household receives $15 gift card after wave 1 completion; $30 after wave 2 completion

• Approximately 3 contacts per household– graphic display of findings (~3 months after wave 1)– Seattle only: letter about wave 2 survey delay – After pricing: mini-survey to engage respondents and obtain

initial feedback on tolling– Household update survey (several weeks prior to wave 2 survey)

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Wave 1 Response

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ModalSegment

Wave 1: Total invitations distributed

Wave 1 Completions

Percentcompleted

Auto 31,282 2908 9.3%

Transit 2,513 396 15.8%

Vanpool 520 52 10%

Total 37,983 3356

NOTES: “Completion” = All adult members of the household completed all surveys

Household Completion Rates by Recruitment Mode

Seattle (November 2010)

Atlanta (April/May 2011)

Household Completion Rates by Recruitment Mode

Modal Segment

Goal for Wave 1

Goal for Wave 2

Auto 2600 1300

Transit + vanpool

400 200

Total 3000 1500

ModalSegment

Wave 1: Total invitations distributed

Wave 1 Completions

Percentcompleted

Auto 35,455 2090 5.8%

Transit 2,721 303 11.1%

Vanpool 477 19 3.9%

Total 38,653 2412

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Wave 1 Methodology Notes• Respondent Burden

– Rough estimates come from RSG data on respondents’ web-based survey times

– This does not include time for filling in Memory Joggers or other work– Averaged 4 minutes per household for initial screener– Approx. 10 minutes per person per day for diary and related questions– 44 minutes total for a typical 2-adult household

• Item Non-Response:– Essentially none due to design of online survey– ~10% selected “prefer not to answer” on income question

• Survey medium: – At least 95% of respondents used online tool, but telephone option was

available and used

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Methodology Notes, continued

• Non-response Bias:– Analyzed via comparison of completed surveys against

partial completions and external benchmarks (including other corridor studies, Census, and Acxiom data)

– Household size appears to be the only key variable with a bias – the achieved sample has fewer large households

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Lessons Learned

• Pilot your survey• Spend the extra time needed to develop a high quality

online survey; provide clear, concise directions– Pop-up windows, map of corridor

• Advance planning is critical– License plate capture process differs by state

• Be flexible– Added travel days in Atlanta to boost response rate

– Enhanced panel maintenance with “mini-survey” to engage respondents

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Next Steps

• Focus groups in Seattle (February 2012)

• Panel maintenance “mini-survey” in Seattle and Atlanta (January/February, 2012)

• Final version of wave 2 surveys

• Household update and wave 2 survey administration

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Comments? Questions?

Margaret Petrella, Social ScientistThe Volpe Center

Margaret.Petrella@dot.gov