TRL Report 367: High and low speed skidding resistance: the influence of texture depth

  • Published: TRL, 1998
  • Authors: P. G. Roe, A. R. Parry, H. E. Viner
  • Date Added: 06 Mar 2013
  • Last Update: 25 Oct 2016
  • Format: html

Objectives:

The provision of adequate friction between the tyre and the road surfacing, especially in wet conditions, is a key factor contributing to road safety. Over many years, research has enabled specifications to be developed which allow newly laid surfaces in the UK to be designed to provide adequate skidding resistance performance for their expected life.

These requirements are further supported by Standards for the skidding resistance of in-service roads which include routine monitoring of low-speed skidding resistance. Since the time of the research on which current standards are based, traffic volumes have increased. Also, an increasing number of proprietary materials have been developed that were not covered by the earlier work.

Therefore, given the importance attached to skidding resistance policy in the UK, the Highways Agency commissioned further research which would re-visit the earlier work and assess the influence of texture on the relationship between high- and low-speed skidding resistance for the wide range of surfaces now used on UK trunk roads. This report describes the main programme of this project and the results of the first phase of analysis.

Methodology:

A database has been built from measurements of friction and texture depth on a wide range of surfacing types. This includes examples of all the major surfacing types used on main roads in the UK, together with some additional surfaces on the TRL test track. Where possible, a range of levels of low-speed skidding resistance and a range of texture depths representative of each surfacing type have been sampled.

Key Findings:

  • Tyre/road friction in dry conditions is generally high but the presence of even a very thin film of water dramatically reduces the coefficient of friction.

Themes:

Skid resistance, Texture

Comments:

Useful UK-based research.

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