Evaluating outcomes of raising speed limits on high speed non-freeways.

Details

• Creators:
  Gates, Timothy ; Savolainen, Peter ; Kay, Jonathan ; Finkelman, Jacob ; Davis, Amelia
• Corporate Creators:
  Wayne State University
• Subject/TRT Terms:
  • Speed limits
  • Traffic crashes
  • Crash severity
  • Fuel consumption
  • Infrastructure
  • Travel time
  • Benefit cost analysis
  • Risk analysis
  • 65 mph speed limit
• Publication/ Report Number:
  RC-1609B
• Resource Type:
  Tech Report
• Geographical Coverage:
  Michigan
• Corporate Publisher:
  Michigan. Dept. of Transportation. Office of Research Administration
• Abstract:
  The purpose of this research was to assist in determining the potential impacts of implementing a ; proposed 65 mph speed limit on non-freeways in Michigan. Consideration was given to a broad range of ; performance measures, including operating speeds, traffic crashes and crash severity, infrastructure costs, ; fuel consumption, and travel times. Specifically, a prioritization strategy was developed to identify ; candidate MDOT non-freeway road segments possessing lower safety risks and potential infrastructure ; costs associated with raising the speed limit from 55 to 65 mph. Ultimately, approximately 747 miles of ; undivided and 26 miles of divided 55 mph non-freeways were identified as lower risk candidates, ; representing approximately one-eighth of the MDOT systemwide mileage posted at 55 mph. An ; economic analysis of the anticipated costs and benefits associated with the proposed speed limit increase ; was performed for these lower risk candidate segments, in addition to a systemwide estimate. As the ; travel time savings were expected to outweigh the fuel consumption costs, it was necessary to determine ; if these net operational benefits outweighed the expected infrastructure upgrade costs and increased crash ; costs. For roadways possessing horizontal and/or vertical alignments that are not compliant with a 65 ; mph speed limit, an unfavorable benefit/cost ratio would likely result due to the excessive infrastructure ; costs incurred during 3R (resurfacing, restoration, rehabilitation) or 4R (reconstruction) projects. Crashes ; were expected to increase for all implementation scenarios, with a particular increase in the risk of fatal ; and incapacitating injuries. Due to the substantially large infrastructure costs, application of the 65 mph ; speed limit is specifically not recommended for non-freeway segments requiring horizontal or vertical ; realignment to achieve design speed compliance. Even for segments where compliance with the ; increased design speed is maintained, careful consideration must be given to the potential safety impacts – ; particularly to fatal and injury crashes – that may result after increasing the speed limit.
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• Format:
  PDF
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/28825/dot_28825_DS1.pdf
• File Type:
  [PDF - 1.30 MB]
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha-512:5cadbc7e5787ba42576a92c6c217e3e301ebdc02a86707b98d8ca63ac29c2370a20363815ecd77a8f08433c66d94b883a59bf317f41f7f60861fca6fb04db8ec