Before/After Study on the Effects of Signage and Striping on the Safety of a Modern Two-Lane Roundabout

This paper presents the study of the impact striping and signing have on driving behavior at a two-lane roundabout located in Richfield, Minnesota. After its completion, this roundabout exhibited a suspiciously high amount of crashes. In response, engineers experimented with changes in the roundabout’s signs and striping, as roundabout design regulations are relatively lax and non-specific in contrast to ones 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 reduction of 48% in normalized occurrences of improper turns, and a normalized 53% reduction of drivers choosing the incorrect lane a month after the changes while a year later these reductions were 44% and 50%, respectively.

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• Supplemental Notes:
  • This paper was sponsored by TRB committee ANB75 Roundabouts. Alternate title: Before-and-After Study on Effects of Signage and Striping on Safety of Modern Two-Lane Roundabout.
• Corporate Authors:

  Transportation Research Board

  500 Fifth Street, NW
  Washington, DC  United States  20001
• Authors:
  • Richfield, Veronica
  • Hourdos, John
  • Asher, Kristin
• Conference:
  • Transportation Research Board 93rd Annual Meeting
  • Location: Washington DC
  • Date: 2014-1-12 to 2014-1-16
• Date: 2014

Language

• English

Media Info

• Media Type: Digital/other
• Features: Figures; References; Tables;
• Pagination: 19p
• Monograph Title: TRB 93rd Annual Meeting Compendium of Papers

Subject/Index Terms

• TRT Terms: Before and after studies; Behavior; Drivers; Highway safety; Roundabouts; Striping; Traffic safety; Traffic signs
• Geographic Terms: Richfield (Minnesota)
• Subject Areas: Highways; Operations and Traffic Management; Safety and Human Factors; I82: Accidents and Transport Infrastructure;

Filing Info

• Accession Number: 01520743
• Record Type: Publication
• Report/Paper Numbers: 14-4584
• Files: PRP, TRIS, TRB, ATRI
• Created Date: Mar 31 2014 3:03PM