Montana's Roundabout Corridor

In Billings, Montana, a 4.5-mi (7.2- km) stretch of two-lane Shiloh Road was becoming increasingly congested. This article describes the innovative approach that was used to improve the safety and mobility of the road. In 2002, the Montana Department of Transportation (MDT) and the Federal Highway Administration initiated an environmental assessment to explore options for improving Shiloh Road. The environmental assessment compared multilane roundabouts to traffic signals at eight intersections. The analysis determined that a corridor of eight roundabouts would offer a better level of service than would signalized intersections. In addition, the roundabouts would cut travel times, reduce crash and severity rates, enhance capacity, and limit the need for property acquisition. The roundabout option also would address access control and other community objectives more effectively and be less expensive overall than the entirely signalized alternative. To alleviate public concerns about the multilane roundabouts, a roundabout demonstration was conducted to show how passenger vehicles, large trucks and emergency vehicles could navigate the roundabout. Most of the Shiloh Road roundabouts have two entering lanes with gore striping, which separates the adjacent lanes and provides for the large, sweeping turning movement of tractor-trailer combinations. This design feature also helps achieve the desired entry speed, which is less than 20 mph (32 km/h). The road surface in the roundabouts is asphalt, but the interior truck aprons are raised, stamped red concrete. American Recovery and Reinvestment Act funds were used in the project. Overall, MDT officials report that the as-constructed traffic conditions at the roundabouts are generally meeting expectations with few exceptions, and travel times are better than expected.

• Record URL:
  • http://www.fhwa.dot.gov/publications/publicroads/12janfeb/02.cfm
• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/oclc/1586080
• Authors:
  • Woodmansey, Alan
  • Spalding, Kirk
• Publication Date: 2012-1

Language

• English

Media Info

• Media Type: Print
• Features: Photos;
• Pagination: pp 8-11
• Serial:
  • Public Roads
  • Volume: 75
  • Issue Number: 4
  • Publisher: Federal Highway Administration
  • ISSN: 0033-3735
  • Serial URL: https://www.fhwa.dot.gov/publications/publicroads/
• Publication flags:

  Open Access (libre)

Subject/Index Terms

• TRT Terms: Case studies; Financing; Highway design; Intersections; Roundabouts
• Geographic Terms: Billings (Montana)
• Subject Areas: Design; Highways; Operations and Traffic Management; I20: Design and Planning of Transport Infrastructure; I72: Traffic and Transport Planning;

Filing Info

• Accession Number: 01372550
• Record Type: Publication
• Files: TRIS
• Created Date: Jun 14 2012 10:56AM