Safety evaluation of signal installation with and without left turn lanes on two lane roads in rural and suburban areas.

Details

• Creators:
  Srinivasan, Raghavan ; Lan, Bo ; Carter, Daniel
• Corporate Creators:
  University of North Carolina at Chapel Hill. Highway Safety Research Center
• Corporate Contributors:
  United States. Federal Highway Administration
• Subject/TRT Terms:
  • Rural areas
  • Suburbs
  • Signalized intersections
  • Left turn lanes
  • Two lane highways
  • Before and after studies
  • Signalization
  • Traffic accidents
  • Traffic safety
  • Accident data
• Publication/ Report Number:
  FHWA/NC/2013-11
• Resource Type:
  Tech Report
• Geographical Coverage:
  North Carolina
• Corporate Publisher:
  North Carolina. Dept. of Transportation. Research and Analysis Group
• Abstract:
  Data from 117 intersections on two lane roads in rural and suburban areas in North Carolina were used to determine the safety ; effect of signalization with and without left turn lanes. This was a before-after study that was conducted using the empirical ; Bayes method. Before signalization, all the 117 intersections were controlled by stop signs on the minor legs. As part of ; implementing the empirical Bayes method, safety performance functions were estimated using data from a reference group of ; minor road stop controlled intersections. Results have been provided for three and four leg intersections separately. Five ; types of crashes were investigated: total, injury and fatal, rear end, frontal impact (type 1), and frontal impact (type 2). ; It is clear that the introduction of signals without the addition of left turn lanes resulted in a reduction in total crashes, injury ; and fatal crashes, and frontal impact crashes (both types), and an increase in rear end crashes. When left turn lanes were ; added, rear end crashes decreased as well. Injury and fatal crashes and rear end crashes benefited the most from the addition ; of left turn lanes. Overall, frontal impact crashes did not benefit from the addition of the left turn lanes. These results along ; with information about the cost of adding left and right turn lanes could be used by NCDOT to determine the locations where ; these turn lanes would be most cost-effective.
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• Format:
  PDF
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/28248/dot_28248_DS1.pdf
• File Type:
  [PDF - 1.71 MB]
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha256:ff48a862c627cea571405d5af1ad529451424ab3ee511557eed155c0897bc883