Performance evaluation of roundabouts for traffic delay and crash reductions in Oxford, MS.

Details

• Creators:
  Uddin, Waheed
• Corporate Creators:
  University of Mississippi. Dept. of Civil Engineering
• Corporate Contributors:
  Mississippi. Dept. of Transportation. Research Division
• Subject/TRT Terms:
  • Highway capacity
  • Roundabouts
  • Traffic delays
  • Crash data
  • Crash rates
  • Traffic congestion
  • Traffic engineering
  • Traffic flow
  • Traffic safety
  • Traffic surveys
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• Publication/ Report Number:
  FHWA/MS-DOT-RD-11-213 ; MS-DOT-RD-11-213
• Resource Type:
  Tech Report
• Geographical Coverage:
  Mississippi
• Edition:
  Final report; June 30, 2011.
• Corporate Publisher:
  Mississippi. Dept. of Transportation
• Abstract:
  Due to increased traffic volume, congestion, and capacity limitations, two roundabouts have been constructed on South Lamar ; Boulevard ramp intersections with MS Highway 6 in Oxford, MS. Roundabouts replaced the existing signalized intersection ; on the north and stop controlled intersections on the south side of the South Lamar Boulevard and MS Highway 6 Interchange. ; The overall objective of this study was to assess the performance of the roundabouts in Oxford with respect to traffic flow, ; capacity, and safety improvements, and to determine the public perception of roundabouts by means of an opinion survey. ; Detailed post-roundabout traffic movement volume and crash data were collected and compared with the pre-roundabout data ; to assess the in-service performance of the roundabouts. Traffic flow microsimulation and capacity analysis methods were ; used to evaluate performance of the roundabouts. The results of the Oxford roundabout study showed significant improvement ; in traffic flow, crash reduction, and reduction in vehicle emissions. It was found that the conversion of the intersections to ; roundabouts improved traffic flow by reducing average delay by 24%, idling time by 77%, and fuel wastage by 56%. Overall ; vehicle emissions from idling were reduced significantly including 56% in CO2, 80% in VOC, and 77% in CO, NOx, and PM10. ; This conversion of stop-controlled intersections to roundabouts increased the average speed by 67% and improved level of ; service of both roundabouts. The roundabout conversion increased the mean speed on the South Lamar interchange by 67% ; and improved level of service for both intersections. The roundabout junctions improved safety performance through a 37.5% ; reduction in crashes and a 60% reduction in the number of crashes resulting in injury. The reduction in overall crashes in the ; study area reduced comprehensive cost by 54.4%. Total user cost saving from reductions in travel time, fuel wastage, and ; crash cost combined is $806,018 annually. These benefits paid off the total cost of construction of the two roundabouts within ; two years. The resulting B/C ratio is 6.2 over a period from 2009 to 2016. Additionally, significant societal benefits are ; expected from reductions in vehicle emissions. Also, an anonymous public opinion survey overwhelmingly demonstrated ; favorable results and provides support to consider more roundabout junctions in place of stop-controlled intersections. The ; study results indicate that roundabouts are performing well as intended. Some constructive comments suggested by the public, ; such as flashing lights on signs, can be implemented by the Mississippi DOT to enhance traffic flow and safety.
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• Format:
  PDF
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/24083/dot_24083_DS1.pdf
• File Type:
  [PDF - 2.93 MB]
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha-512:e23e0bd63f1ac3f3f776f8e81d5fb36fc21e1d54e39cec371e8d3d4a4fd4a1e014a9bbedd38e28eb096ebaa27845126065a09d7bfe75a524bb16a8fa02d1500f