Research Report Resources » Engineering » Roundabouts » Strategies for Effective Roundabout Approach Speed Reduction

Strategies for Effective Roundabout Approach Speed Reduction

Final Report 2017-14

  • Posted: Monday May 1st, 2017
  • Source: Texas Transportation Institute
  • Publishing Organization: Minnesota Department of Transportation, Minnesota Local Road Research Board
  • Topic: Engineering, Road
  • Sub-Topic: Roundabouts, Safety Countermeasures


“Appropriate deceleration on approaches to roundabouts is primarily accomplished through the use of applicable geometric design principles; however, traffic control devices (specifically signing and markings on the approach) also serve a vital role in communicating to the approaching driver what speed profile should be anticipated. This report provides a resource for engineers to identify and select appropriate speed-reduction treatments for high-speed approaches to roundabouts. The research examines best practices and research literature on speed-reduction techniques for high-speed approaches for all intersection types, as well as treatments for work zones and horizontal curves. Based on the findings from these efforts, the report summarizes a selection of treatments including traditional signs with and without beacons, pavement markings, illumination, speed-activated signs, and transition zones. Information on the effectiveness of these treatments, as well as potential costs of installation and maintenance, is provided for the practitioner to determine which treatment(s) best suit the site under consideration. Guidance is also provided for the methodology of conducting a speed study to determine the speed characteristics of a site, as well as links to resources for additional information. The project identifies a number of research needs specific to particular treatments as well as the general need for field research of the recommended countermeasures specifically on approaches to high-speed rural roundabouts.”