Travel Time Savings From a Traffic Web Site

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Travel Time SavingsFrom a Traffic Web Site

• Mike Lowry
• TransNow Student Conference
• February, 9 2006

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Research Question
Advanced Traveler Information Systems (ATIS)
Can ATIS reduce travel time?
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Background

• Trip decisions
• Mode choice
• Departure time
• Route choice
• Trip elimination
• Destination choice

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Background

• Potential user benefits
• Shorter travel time
• Better on-time reliability
• Reduced frustration
• Improved trip planning
• Potential system benefits
• Reduced total delay
• Increased system capacity
• Better system efficiency
• Better air quality

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Past Research

• Surveys
• Field Studies
• HOWLATE
• Mathematical estimations

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Methodology
Simulation of the Bellevue to Seattle
commute Driver 1 Takes I-90 (the
historically quicker route) every day
regardless of traffic conditions Driver 2
Chooses a route based on the traffic website
with a 15 minute lag before departure (to
account for the delay between checking the
website and departure)
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Methodology

• Analysis
• Descriptive statistics
• Paired t-test to compare mean travel times
• Data
• Predicted Travel Times from WSDOT
• Actual Travel Times from TRAC
• Every 5 minutes for every week-day in 2003

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Travel time savings from using the website
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Results
Bellevue-Seattle 6 pm Commute 246 days of
analysis Driver 1 avg travel time was 18.1
minutes Driver 2 changed route 68 times (i.e.
chose SR 520) Greatest savings 12.3
minutes Average savings 0.7
minutes Worst loss 5.7 minutes Worse
off 7 No savings/loss 72 Better
off 21 1 min or more 18
5 min or more 8 10 min or more
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Frequency of savings from using the website
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Enroute ATIS
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Affect of lag time on travel time savings
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Summary

1. Average travel time savings were very low (0.7
   min)
2. Significant savings were rare (10 min or more,
   1)
3. Savings were greatest during peak periods
4. Savings were greatest when lag time is minimal

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Future Research

• This methodology
• Other commutes in the Puget Sound
• Other modes
• Relationship between incidents and savings
• Other user benefits (on-time reliability,
  frustration relief)
• System benefits

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