Impacts of Area-Wide Air Pollution on Multimodal Traffic Volumes in Utah

During area-wide episodes of poor air quality, people may reduce their transportation-related emissions by driving less, reducing their exposure to emissions by walking/bicycling less, or going about their lives as usual. These three reactions have different consequences for transportation, health, and the environment. This study investigated the aggregate effects of air pollution on multimodal traffic volumes by comparing associations of the daily air quality index with pedestrian and automobile traffic volumes (collected at many different locations) and system-wide bus/rail ridership over a two-year period in two regions of Utah, United States. The authors used multilevel modeling to measure how these relationships differ by mode and across locations, while controlling for weather and investigating built/social environmental characteristics. Overall, the authors found strong evidence that pedestrian volumes declined by 10% or more, on average, on days where the air quality was "unhealthy for sensitive groups" (orange). There was some evidence that automobile traffic volumes increased on poor air quality days, especially on the way to mountainous recreation areas surrounding urban valleys. Decreases in bus/rail ridership were not statistically significant. Overall, there was more evidence for "risk averse" reactions than for "altruistic" travel behavior changes, suggesting that newer or stronger policies may be needed in order to reduce driving and encourage more sustainable and healthful travel behavior changes in regions when faced with periods of area-wide poor air quality.

• Record URL:
  • https://www.ugpti.org/resources/reports/details.php?id=1201
• Record URL:
  • https://rosap.ntl.bts.gov/view/dot/78694
• Summary URL:
  • https://rosap.ntl.bts.gov/view/dot/78765
• Supplemental Notes:
  • This document was sponsored by the U.S. Department of Transportation, University Transportation Centers Program.
• Corporate Authors:

  Utah State University, Logan

  Civil and Environmental Engineering Department
  Logan, UT  United States  84332

  Mountain-Plains Consortium

  North Dakota State University
  Fargo, ND  United States  58108

  Office of the Assistant Secretary for Research and Technology

  University Transportation Centers Program
  Department of Transportation
  Washington, DC  United States  20590
• Authors:
  • Singleton, Patrick A
  • Tiwari, Prachanda
  • Park, Keunhyun
• Publication Date: 2024-9

Language

• English

Media Info

• Media Type: Digital/other
• Edition: Final Report
• Features: Figures; Maps; References; Tables;
• Pagination: 56p

Subject/Index Terms

• TRT Terms: Air quality; Automobile travel; Pedestrian traffic; Ridership; Traffic volume; Travel behavior
• Geographic Terms: Utah
• Subject Areas: Environment; Highways; Operations and Traffic Management; Pedestrians and Bicyclists; Public Transportation; Safety and Human Factors;

Filing Info

• Accession Number: 01938757
• Record Type: Publication
• Report/Paper Numbers: MPC-662, MPC-24-554
• Files: UTC, NTL, TRIS, USDOT
• Created Date: Dec 5 2024 9:38AM