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473700-00072-1 Report Abstract

An Investigation on the Environmental Benefits of a Variable Speed Control Strategy

Zhong Wang and C. Michael Walton, University of Texas at Austin, September 2006, 58 pp. (473700-00072-1)

The safety benefits of variable speed limits (VSL) have already been widely recognized. However, the environmental benefits of variable speed limits have been largely ignored. This paper presents a study of the potential benefits of variable speed limits in reducing mobile emissions. A Monte Carlo simulation approach is developed to evaluate the effectiveness of the idea of using variable speed limits to manage and reduce mobile emissions. A case study is performed on the IH-35 corridor in Austin, Texas. The numerical results indicate that on “Ozone Action” days, by managing the freeway/expressway traffic speeds at appropriate levels through VSL, the major pollutants, such as Nitrogen Oxides (NOx) emissions, could be significantly reduced. Considering the large contribution from freeway/expressway traffic to mobile emissions, a variable speed limit strategy could be an effective measure to balance travelers’ need for mobility with conservation of the environment.

Keywords: Air Quality, Emissions, Variable Speed Limit

ENTIRE REPORT (Adobe Acrobat File – 631 KB)