Evaluating Alternative Operations Strategies to Improve Travel Time ...

SHRP 2 L11: Final Appendices
The integration of a simulation model with optimization techniques showed that delays at grade crossings can be reduced by up to
8% (17)
Traffic Adaptive Signal Control/Advanced Signal Systems
• Safety: The deployments of adaptive signal control systems—in Scottsdale, Arizona; Oxnard, California; San Francisco,
California; Howard County, Maryland; New York, New York; Fairfax, Virginia; and Minnesota—resulted in crash reductions
ranging from 24 to 70 percent (45).
• Mobility: Adaptive signal control systems have been shown to reduce peak period travel times 6-53% by field studies in several
cities (1).
Adaptive signal control integrated with freeway ramp meters in Glasgow, Scotland increased vehicle throughput 20% on arterials
and 6% on freeways (2).
In Los Angeles, Broward County and Newark, travel time decreased by 13 to 25 percent (3).
Application of ACS-Lite (FHWA adaptive control software) in Gahanna, OH; Houston, TX and Bradenton, FL resulted in travel
time reductions of up to 11% and due signal timing optimization. Delay reduction were estimated to be up to 35%. (9).
Adaptive Signal Systems implementation in San Antonio, Houston and Atlanta has shown total savings in travel time ranging from
95,000 to 2 million hours (11).
The implementation of the SCOOT (adaptive control technique) System in Gasgow and Conventry, UK reduce average delay at
traffic signals by approximately 12% (33).
The Automated Traffic Surveillance and Control System (ATSAC) in Los Angeles reported in 1994 an 18% reduction in travel
time and a 44% reduction in delay (33).
The SCATS (Sydney Coordinated Adaptive Traffic System) deployment in Park City, Utah, reduced travel times for the AM
weekday period by an average of 7.6% and 3.9% for the PM weekday period. Weekend travel times were reduced by 1.9%. Travel
time stopped delay was also reduced during “SCATS On” by approximately one-half minute on the weekend to one full minute
during the weekday, or 13% to 20% respectively (44).
• Efficiency: The Traffic Light Synchronization program in Texas shows a benefit-to-cost ratio of 62:1, with reductions of 24.6
percent in delay, 9.1 percent in fuel consumption, and 14.2 percent in stops (1).
A 2005 Oakland Metropolitan Transportation Commission analysis of its traffic signal coordination program yielded a benefit-tocost
ratio of 39:1 (2).
ADDITIONAL DESCRIPTION AND QUANTITATIVE BENEFITS OF TRAVEL-TIME RELIABILITY STRATEGIES Page F-37