Effect of Signing and Lane Markings on the Safety of a Two-Lane Roundabout

This report presents a study of the impact lane markings and signing have on driving behavior at a two-lane roundabout located in Richfield, Minnesota. After its completion in 2008, this roundabout sustained a suspiciously high amount of crashes. In response, through this study, engineers experimented with changes in the roundabout’s signs and lane markings, as roundabout design regulations are relatively lax and nonspecific in contrast to those for standard signalized intersections. An observational study was conducted that reduced 216 hours of before and after video records of the roundabout into a database of all the violations committed by drivers. Along with the observational data, crash records were analyzed and demonstrated that improper turns and failing to properly yield account for the majority of collisions. The changes implemented in the approaches to the roundabout and specifically the extension of the solid line seems to have reinforced the message to the drivers that they must select the correct lane before approaching the roundabout entrance. Although choosing the correct lane does not directly address yielding violations, it does reduce the occurrence of drivers conducting an improper turn and to some extent reduces the need for a driver to change lanes within the roundabout. The implemented changes produced a 48% reduction in normalized occurrences of improper turns, and a 53% reduction in normalized occurrences of drivers choosing the incorrect lane a month after the changes, while a year later, these reductions were 44% and 50%, respectively.

• Record URL:
  • https://hdl.handle.net/11299/162826
• Record URL:
  • https://hdl.handle.net/20.500.14153/mndot.4260
• Record URL:
  • https://hdl.handle.net/20.500.14153/mndot.2948
• 
• Summary URL:
  • http://www.cts.umn.edu/Publications/researchsummaries/documents/roundabouts.pdf
• Summary URL:
  • http://www.dot.state.mn.us/research/TS/2014/201404TS.pdfhttp://www.dot.state.mn.us/research/TS/2014/201404TS.pdf
• Corporate Authors:

  University of Minnesota, Minneapolis

  Department of Civil Engineering
  500 Pillsbury Drive, SE
  Minneapolis, MN  United States  55455-0116

  Minnesota Department of Transportation

  Research Services and Library
  395 John Ireland Boulevard
  St Paul, MN  United States  55155
• Authors:
  • Hourdos, John
  • Richfield, Veronica
• Publication Date: 2014-1

Language

• English

Media Info

• Media Type: Digital/other
• Edition: Final Report
• Features: Appendices; Figures; Photos; References; Tables;

Subject/Index Terms

• TRT Terms: Before and after studies; High risk locations; Lane lines; Roundabouts; Traffic safety; Traffic signs
• Geographic Terms: Richfield (Minnesota)
• Subject Areas: Highways; Operations and Traffic Management; Safety and Human Factors; I73: Traffic Control;

Filing Info

• Accession Number: 01506099
• Record Type: Publication
• Report/Paper Numbers: 2014-04, CTS Project # 2012002
• Contract Numbers: (C) 89261 (WO) 271
• Files: TRIS, ATRI, STATEDOT
• Created Date: Jan 30 2014 12:48PM