As of October 1, 2016, the SWUTC concluded its 28 years of operation and is no longer an active center of the Texas A&M Transportation Institute. The archived SWUTC website remains available here.

467312-1 Report Abstract

Fuel Consumption Estimation and Optimal Traffic Signal Timing

Tsai-Yun Liao and Randy B. Machemehl, University of Texas at Austin, August 1998, 179 pp. (467312-1)

Growing concern about environmental protection and energy conservation has led the Clean Air Act Amendments and a number of studies to increase fuel economy and reduce emissions. Since most of the United States fuel consumption is by the transportation sector and fuel consumed by vehicles is about 75% of all transportation energy used, developing ways to reduce vehicle fuel consumption in traffic systems has become an important task. Furthermore, high gasoline consumption worsens air quality in urban areas by emission of carbon monoxide (CO) and carbon dioxide (CO2), which makes these areas, especially in the vicinity of intersections, potentially dangerous to human health.

The objectives of this report are to develop an analytical model to estimate fuel consumption and to investigate the effects of signal timing on fuel consumption. Several numerical experiments, including a variety of geometric configurations, traffic conditions, and signal timing are conducted to test the AFCM estimation capability and to investigate the effects of signal timing on fuel consumption. The results from these experiments indicate that total fuel consumption, with respect to signal cycle time, possesses a convex pattern.

In order to analytically establish the relationship between fuel consumption and signal timing, a three-term form is reduced from the AFCM to represent major effects of vehicle characteristics, traffic behavior, and fuel consumption parameters on optimal cycle length. The first term represents vehicle idle fuel consumption, the second term describes vehicle fuel consumption during acceleration after a stop, and the third term accounts for stochastic effects. Numerical analysis and comparisons show that the optimal cycle lengths from the expression are rather close to those from the AFCM.

Keywords: Fuel Consumption Model, Signalized Intersections, Vehicle Speed, Signal Timing, Optimal Cycle Lengths, Acceleration, Deceleration

ENTIRE REPORT (Adobe Acrobat File – 2.4 MB)