Analysis of the Relative Efficiency of Freeway Congestion Mitigation as an Emission Reduction Strategy

In order to move toward better understanding of freeway congestion mitigation and emissions reduction strategies, this paper explores the effects of traffic speeds, freeway capacity, travel demand, and alternative efficiency strategies on freeway emissions. Emissions from a homogeneous freeway section with typical fleet and traffic characteristics are modeled and analyzed utilizing widely established emission models and macroscopic speed-flow relationships. Assuming an inelastic travel demand function, it is observed that the potential for marginal emissions rate reductions through average travel speed adjustments between 30 and 65 mph is small – though larger rate reductions are possible by moderating speeds that are outside this range. If elastic travel demands functions are assumed, then it is observed that capacity expansions that reduce marginal emissions rates by increasing travel speeds are likely to increase total emissions for initial Level of Service E or above. Finally, it is also shown that alternative emissions reduction strategies that do not rely on increasing freeway speed or capacity may be more effective, even assuming an inelastic demand function.

• Corporate Authors:

  Transportation Research Board

  500 Fifth Street, NW
  Washington, DC  United States  20001
• Authors:
  • Bigazzi, Alexander York
  • Figliozzi, Miguel
• Conference:
  • Transportation Research Board 90th Annual Meeting
  • Location: Washington DC, United States
  • Date: 2011-1-23 to 2011-1-27
• Date: 2011

Language

• English

Media Info

• Media Type: DVD
• Features: Figures; References; Tables;
• Pagination: 18p
• Monograph Title: TRB 90th Annual Meeting Compendium of Papers DVD

Subject/Index Terms

• TRT Terms: Exhaust gases; Flow speed relationships; Highway capacity; Pollutants; Traffic congestion; Traffic mitigation; Traffic speed; Travel demand
• Subject Areas: Environment; Highways; Operations and Traffic Management; I15: Environment; I70: Traffic and Transport;

Filing Info

• Accession Number: 01337450
• Record Type: Publication
• Report/Paper Numbers: 11-3090
• Files: TRIS, TRB
• Created Date: Apr 21 2011 7:25AM