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Appendix A. Summary of Study Project Reported Travel Findings




Major Caveats/Limitations

Simulated Pricing Field Demonstrations

Oregon Mileage Fee Concept and Road User Fee Pilot Program

  • 10% reduction in total VMT
  • 13% reduction in peak hour VMT
  • Peak hour mode choice influenced by the pricing
  • Mileage price incentives can be expected to impact travelers’ total amount of driving, the timing of their trip making, and, potentially, their mode of travel
  • None reported

Puget Sound Traffic Choices Study

  • 7% reduction in total weekly vehicle trips
  • 12% reduction in weekly VMT
  • 8% reduction in total weekly travel time
  • 13% reduction in weekly VMT on tolled roads
  • Motorists made small-scale adjustments in travel that, in aggregate, would have a major impact on transportation system performance
  • Households that modified their travel did so in many different ways: fewer and shorter vehicle trips, alternate routes and times of travel, or linking trips together to reduce vehicle use altogether
  • Responses to congestion charging may be underestimated in so much as some households who may have been inclined to avoid the peak period charges did not have the flexibility to do so

Commute Atlanta Mileage Based Value Pricing Demonstration

  • 3% reduction in total VMT
  • Little if any project impact.  Observed VMT reduction thought to be a function of non-project related changes in travel behavior
  • Inter- and intra-household variability and demographic instability obscured any project impact
  • Higher income respondents were somewhat over-represented in the survey

Before-After Project Evaluations – U.S.

Minnesota I-394 MnPASS HOT Lanes

  • Up to 5% increase in peak hour corridor throughput
  • 6% average increase in speeds in general purpose lanes
  • Speeds increased in the general purpose lanes and MnPASS lane for many locations
  • Travel times generally unchanged or slightly increased
  • Project benefits distributed relatively evenly amongst population
  • The public supported the HOT lane concept
  • MnPASS users were satisfied with toll operations
  • None reported

San Diego I-15 HOT Lanes

  • 48% increase in express lane traffic volumes
  • 76% of FasTrak customers would leave at a different time in the morning if there were no FasTrak.
  • I-15 pricing project alleviated congestion on the I-15 main lanes by redirecting an increasing share of volume onto the I-15 express lanes
  • Dynamic pricing structure was able to create desirable redistribution of a portion of express-lane traffic from the middle of the peak to the shoulders
  • Exogenous factors played a more significant role than the project in regard total traffic increases in the I-15 corridor

Before-After Project Evaluations – International

The Stockholm Trial

  • 16-24% reduction in peak hour traffic volumes
  • 14% reduction in VKT in charging zone
  • 33-50% reduction in peak hour average queue wait times
  • 3% reduction in average journey (travel) times
  • The project was successful in managing congestion and increasing flow and accessibility
  • The impact of other projects and fuel price changes were not completely controlled
  • Car trips across the pricing zone decreased by 20 percent
  • No project-attributable changes in walking, bicycling, telecommuting or carpooling
  • Trip chaining increased slightly
  • The pricing project shifted trips to transit
  • Exogenous factors, including fuel price changes and seasonal variation limit the strength of conclusions
  • 6% increase in total transit ridership
  • 4% decrease in the proportion of transit users that are satisfied with service quality
  • Increases in transit use met or exceed expectations
  • Goals for maintaining transit rider satisfaction were not achieved due to crowding and reduced schedule adherence
  • Increases in transit uses may also have been impacted significantly by fuel prices and economic development

London Congestion Pricing

  • 15% reduction in VKT after first year
  • 18% reduction in number of vehicles entering the pricing zone
  • 25% reduction in delays
  • 14% reduction in journey times
  • 21% increase in speeds
  • The project has succeeded in its fundamental objectives in reducing congestion
  • Impossible to precisely and definitively isolate project impacts from exogenous factors impacts
  • 37% increase in passengers entering central zone by bus
  • 30% decrease in excess bus wait time in first year
  • 20% reduction in bus kilometers not operated due to congestion
  • Transit has accommodated significantly increased passenger levels with limited adverse impacts
  • Transit performance has been improved in some respects as a result of reduced roadway congestion and transit service enhancements
  • Exogenous factors have influenced transit ridership and performance but some estimation of project-specific impacts are possible
  • (Central charging zone) 50-60% of trips formally made by car now made by transit; 20-30 percent driving around the charging zone; 8-10 percent bicycling, motorcycling or walking; <1% eliminated trips; and <1 shifted car trip to non-priced times
  • The charging scheme has resulted in significant travel behavior changes, with most trips shifting to transit
  • Being based largely on surveys, despite best efforts, some groups are likely over or under-represented

Singapore Area Pricing

  • 44% reduction in traffic volumes into the priced zone
  • Share of HOV 4+ trips increased from 8 to 19%; bus share increased from 33 to 46%
  • A.m. peak speeds inside priced zone increased by 20% or more
  • Speeds increased 10% on inbound roadways leading to the priced zone
  • Motorists shifted trips to non-priced times and routes
  • The pricing projects, coupled with other strategies, have been effective in providing lasting, significant reductions in traffic congestion
  • None reported.


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