Estimating Impact of Nonrecurring Congestion on Vehicle Emissions

The nonrecurring congestion due to incidents results in not only increased delays and road user costs, but also increased mobile source emissions as well, primarily due to the increased idling . Although it has been widely recognized that such increased emissions are an important variable to be quantified in order to accurately evaluate the level of severity of the incidents, more specifically the impact of such incidents on the regional air quality, however, very few studies have been conducted so far on the quantification of mobile emissions caused by the nonrecurring congestions, and there exist no viable methodologies available for measuring such emissions. Therefore, this paper is intended to develop methodologies and procedures for estimating idling emissions caused by nonrecurring congestions due to incidents. The paper provides two levels of estimations, the microscopic level and the macroscopic level, both of which are feasible approaches for estimating idling emissions due to incidents. The microscopic estimation focuses on the extra emissions caused by each individual incident while the macroscopic estimation attempts to estimate the change of emission factors for the entire region. Through a case study in the greater Houston area, it is found that the change of emission factors estimated by both methods falls into the same or close ranges. Both methods result in that the impacts of the nonrecurring congestion on the air quality due to incidents in the greater Houston area are significant.


  • English

Media Info

  • Media Type: CD-ROM
  • Features: Figures; References; Tables;
  • Pagination: 23p
  • Monograph Title: TRB 86th Annual Meeting Compendium of Papers CD-ROM

Subject/Index Terms

Filing Info

  • Accession Number: 01043568
  • Record Type: Publication
  • Report/Paper Numbers: 07-0427
  • Files: TRIS, TRB
  • Created Date: Feb 8 2007 5:00PM