Evaluating Alternative Operations Strategies to Improve Travel Time ...

SHRP 2 L11: Final Appendices
confirmed.) However, other indirect measures, such as improvements to mobility and safety are
described below (from Appendix E):
Efficiency
• The benefit-to-cost ratio of the Minneapolis-St. Paul ramp metering system was found to be
15:1. (1)
Mobility
• A ramp metering study in Salt Lake Valley, Utah showed that with an 8 second metering
cycle, mainline peak period delay decreased by 36 percent, or 54 seconds per vehicle. (1)
• Freeway volume declined by 9% and peak period throughput decreased by 14% after ramp
meters were experimentally turned off in the Minneapolis-St. Paul area. (5)
• Five ramp meter pilot projects were tested on the A40 motorway in Germany. The results
showed that congestion decreased by more than 50% during peak periods and traffic
incidents at the ramps decreased by 40%. (6)
• Ramp meters in the Netherlands have helped to regulate traffic flow on highways, have led
to measured speed increases, and have allowed for capacity increases of up to 5%. (7)
• Ramp meters at the Oakland-Bay Bridge toll facility in San Francisco, CA resulted in an
overall average travel time decrease of 16.5% and a site specific travel time savings of
between 2.5 and 3.5 minutes per vehicle. (8)
Safety
• Crash frequency increased by 26 percent after the ramp meter system on Minneapolis-St.
Paul freeways was deactivated. (1)
• A survey of traffic management centers in eight cities found that ramp meters reduced the
accident rate by between 24 and 50%. (2)
Energy/Environment
• Ramp meters saved between 2% and 55% of the fuel expended at each ramp in a
simulation study in Minneapolis-St. Paul. (1)
SAMPLE PROBLEM-QUANTIFYING THE ECONOMIC BENEFIT OF IMPROVING TRAVEL-TIME RELIABILITY Page D-13