Decline in Traffic Congestion Increased Crash Severity in the Wake of COVID-19

Highway fatalities are a leading cause of death in the U.S. and other industrialized countries. Using highly detailed crash, speed, and flow data, we show highway travel and motor vehicle crashes fell substantially in California during the response to the COVID-19 pandemic. However, we also show the frequency of severe crashes increased owing to lower traffic congestion and higher highway speeds. This “speed effect” is largest in counties with high pre-existing levels of congestion, and we show it partially or completely offsets the “VMT effect” of reduced vehicle miles traveled on total fatalities. During the first eleven weeks of the COVID-19 response, highway driving decreased by approximately 22% and total crashes decreased by 49%. While average speeds increased by a modest 2 to 3?mph across the state, they increased between 10 and 15?mph in several counties. The proportion of severe crashes increased nearly 5?percentage points, or 25%. While fatalities decreased initially following restrictions, increased speeds mitigated the effect of lower vehicle miles traveled on fatalities, yielding little to no reduction in fatalities later in the COVID period.

• Record URL:
  https://doi.org/10.1177/03611981221103239
• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/03611981
• Supplemental Notes:
  • Daniel Kaffine https://orcid.org/0000-0002-9556-7776© National Academy of Sciences: Transportation Research Board 2022.
• Authors:
  • Hughes, Jonathan E
  • Kaffine, Daniel
  • 0000-0002-9556-7776
  • Kaffine, Leah
• Publication Date: 2023-4

Language

• English

Media Info

• Media Type: Web
• Features: References;
• Pagination: pp 892-903
• Serial:
  • Transportation Research Record: Journal of the Transportation Research Board
  • Volume: 2677
  • Issue Number: 4
  • Publisher: Sage Publications, Incorporated
  • ISSN: 0361-1981
  • EISSN: 2169-4052
  • Serial URL: http://journals.sagepub.com/home/trr

Subject/Index Terms

• TRT Terms: Before and after studies; COVID-19; Crash severity; Traffic congestion; Traffic crashes; Traffic speed
• Geographic Terms: California
• Subject Areas: Highways; Safety and Human Factors;

Filing Info

• Accession Number: 01850793
• Record Type: Publication
• Files: TRIS, TRB, ATRI
• Created Date: Jun 30 2022 9:38AM