Street Network Connectivity, Traffic Congestion, and Traffic Safety

Over the last two decades, street connectivity has gained substantial attention in urban planning circles as a critical environmental aspect to achieve many community goals. Despite advocacy for interconnected areas, the literature on the effects of street connectivity on transportation outcomes is still intuitive. In this study, the authors examine the effect of street connectivity on congestion levels and crash rates in neighborhoods across Utah's Wasatch Front. The authors employ propensity score matching to select pairwise neighborhood samples with similar characteristics that differ greatly in street connectivity. The authors use principal component analysis to develop a connectivity index incorporating multiple aspects of street connectivity. Congestion levels are computed as the Travel Time Index on arterials and collectors. Crash rates are calculated at three different severity levels— total, injury, and fatal. Finally, the authors use t-tests to determine whether significant differences exist between high- and low-connectivity neighborhoods. The results show that more connected neighborhoods have significantly lower congestion levels, but they do not have measurably lower (or higher) crash rates, presumably due to the prevalence of four-way intersections. This study can help guide data-driven decision-making on street connectivity standards for many of the growing urban areas across the country and globe.

• Record URL:
  https://drive.google.com/file/d/1xxnQ1j872VtROVrdnADOuOAIa12Jga-8/view
• Corporate Authors:

  University of Utah, Salt Lake City

  Department of City and Metropolitan Planning, 375 South 1530 East
  Salt Lake City, UT  United States  84112

  Utah Department of Transportation

  4501 South 2700 West
  Salt Lake City, UT  United States  84114-8410

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • Ewing, Reid
  • Choi, Dong-ah
  • Kiani, Fatemeh
  • Kim, Junsik
  • Sabouri, Sadegh
• Publication Date: 2020-9

Language

• English

Media Info

• Media Type: Digital/other
• Edition: Final Report
• Features: Appendices; Figures; Maps; References; Tables;
• Pagination: 52p

Subject/Index Terms

• TRT Terms: Alternatives analysis; Crash rates; Highway design; Neighborhoods; Traffic congestion; Traffic safety
• Geographic Terms: Wasatch Front (Utah)
• Subject Areas: Design; Highways; Operations and Traffic Management; Safety and Human Factors;

Filing Info

• Accession Number: 01760031
• Record Type: Publication
• Report/Paper Numbers: UT-20.19
• Contract Numbers: 20-8076; 5H08274H
• Files: TRIS, ATRI, USDOT, STATEDOT
• Created Date: Nov 24 2020 12:38PM