Evaluating Alternative Operations Strategies to Improve Travel Time ...

SHRP 2 L11: Final Appendices
As a result of queue warning system in Netherlands, a reduction of 15% to 25% in primary incidents and reduction of 40% to 50%
incidents on the system was observed (25).
• Mobility: Dynamic message signs with delay information were found to reduce system delay 6.7% using models of increased
traffic flow at San Antonio rail crossing (1).
Simulation study in Detroit, Michigan showed that DMS combined with ramp metering would reduce vehicle delay by up to 22
percent (3).
ITS Deployment Analysis System (IDAS) program estimates that on average, 11 minutes per traveler can be saved by
implementing DMS systems (4).
Available data shows that Dynamic Message Signs and integrate traveler information with incident management systems can
increase peak period freeway travel speed by 8% to 13%, improve travel time, according to simulation studies, reduce crash rates
and improve trip time reliability with delay reductions ranging from 1 to 22 percent (5).
A study in six European countries showed that an average of 8% of all drivers diverted from their intended route based on the
information displayed by DMSs (6).
As a result of queue warning system in Netherlands, throughput on facilities in the system increased between 4 to 5% (25).
Research suggests that 8% to 10% of drivers react to the information provided on the DMS in Netherlands which may lead to a 0%
to 5% improvement in network performance (27).
• Efficiency: In South Carolina, dynamic message signs and highway advisory radio systems made it easier for hurricane evacuees
to return home during the aftermath of Hurricane Floyd (1999). Traffic volume during the evacuation, when outbound traffic used
only one side of the freeway, was 44 percent less than the traffic volume during the return trip when inbound traffic used both sides
of the freeway (5).
Positive results were found by using DMS to display queue warning information. In the A8 Motorway in German, a pilot study
showed fewer accidents, reduced incidents severity, harmonized speed and slightly increase in capacity (25).
• Customer Satisfaction: 85% of motorists surveyed changed their route after viewing real-time travel time information on freeway
dynamic message signs in Houston (1).
Mail-back questionnaires were sent to 428 drivers living near major freeways in Wisconsin to assess the impacts of posting travel
time and traffic information on DMS throughout the state. A total of 221 questionnaires were returned and analyzed. The results
indicated that 12 percent of respondents used the information more than 5 times per month to adjust travel routes during winter
months, and 18 percent of respondents used the information more than 5 times per month to adjust travel routes during non-winter
months (5).
ADDITIONAL DESCRIPTION AND QUANTITATIVE BENEFITS OF TRAVEL-TIME RELIABILITY STRATEGIES Page F-27