Rethinking How We Manage Traffic to Reduce Emissions While Maintaining Mobility: A New Paradigm for Traffic Management

Principal Investigator(s):

Henry Liu, Former Professor, Civil, Environmental and Geo-Engineering


Project summary:

According to the US Environmental Protection Agency (EPA), transportation is the second largest contributing sector to greenhouse gas emissions. Traditionally, transportation efficiency, accessibility, and safety have been the major factors considered in the traffic management and transportation planning process. It is also generally assumed that traffic management strategies that reduce travel delays reduce emissions. Unfortunately, this is not the case. Reducing average delays traveled does not always reduce emissions. Emissions do not depend only on the average speed of travel but also on the variability of this speed. In particular, patterns of acceleration and deceleration, as well as the frequency of stop and go traffic and idling, can significantly affect emissions. Hence, delay reduction-oriented management of traffic may be inefficient in reducing vehicular emissions. There is clearly a need to investigate current transportation operations and bring emission reduction into the objective of traffic management and transportation planning. The goal of this project is to revisit the fundamentals of traffic operations and introduce emission reduction as a traffic management objective. In particular, we are interested in exploring alternative traffic operation strategies that will reduce emission while maintaining mobility. The main research objectives are (i) to study the impact of operational decisions on emission reduction, (ii) to develop operational models to further the insights of various approaches for reducing traffic emission while maintaining mobility, and (iii) to test alternative traffic management strategies for effective emission reduction.

Project details:

  • Project number: 2011107
  • Start date: 02/2011
  • Project status: Completed
  • Research area: Transportation Safety and Traffic Flow
  • Topics: Environment, Traffic operations