Safety Boosted by Steps in Speed

This article describes how traffic flow has been improved, congestion eased and safety increased by a system of stepped speed limits (SSL) introduced to United Kingdom (UK) roadwork. Studies have shown that road users approach roadwork with differing behaviors. Some motorists brake gradually while others maintain a consistent speed before braking sharply, often in response to visible enforcement of a reduction in speed limit. The result of these different reactions is a tendency for increased lane changing, breakdown in traffic flow and a build-up of queues, increasing risk of accidents on the approach to roadwork. One possible solution to this problem is a system of stepped speed limits (SSL). Typically, SSL involves implementing an additional mandatory speed limit for a short distance on the approach to roadwork 10 mph (16 kph) more than the limit through the works. For example, an additional 60 mph (96 kph) speed limit would be applied prior to a 50 mph (80 kph) speed limit through the roadwork. SSL is not a solution which should be introduced to all roadwork. It is suggested that it is only implemented on major roads where at least one of the following statements applies: (1) there is likely to be an increase in the number of accidents due to the roadwork; (2) where there has been a history of unsatisfactory speed limit compliance; or (3) the existence of roadwork will increase queuing on the approach. On the schemes where SSL is implemented, significant benefits for all stakeholders are expected. Initial micro simulation modeling of SSL indicated that the concept could yield many benefits including reduction in average travel time, increased flow throughput and easing of congestion.

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/oclc/35183091
• Authors:
  • Uff, Jamie
• Publication Date: 2011

Language

• English

Media Info

• Media Type: Print
• Features: Figures; Photos;
• Pagination: pp 60-61
• Serial:
  • ITS International
  • Volume: 17
  • Issue Number: 6
  • Publisher: Route One Publishing Limited
  • ISSN: 1463-6344
  • Serial URL: http://www.itsinternational.com

Subject/Index Terms

• TRT Terms: Highway safety; Queuing; Traffic congestion; Traffic flow; Travel time; Work zone traffic control
• Candidate Terms: Stepped speed limits
• Subject Areas: Highways; Operations and Traffic Management; Safety and Human Factors; I73: Traffic Control;

Filing Info

• Accession Number: 01362799
• Record Type: Publication
• Files: TRIS
• Created Date: Feb 16 2012 10:14AM