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:
  Crash Data Crash Rates Highway Capacity Highway Research--Mississippi Roundabouts Traffic Congestion Traffic Delays Traffic Engineering Traffic Flow Traffic Safety Traffic Surveys Traffic Surveys--Mississippi

  More +
• 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.
  
  
• Format:
  PDF
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha-512:e23e0bd63f1ac3f3f776f8e81d5fb36fc21e1d54e39cec371e8d3d4a4fd4a1e014a9bbedd38e28eb096ebaa27845126065a09d7bfe75a524bb16a8fa02d1500f
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/24083/dot_24083_DS1.pdf
• File Type:
  [PDF - 2.93 MB ]