Skidding resistance of trunk roads

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Next update expected:August 2027

Updates

13th August 2026

This update includes the publication of 2025-26 data.

21st January 2026
Dataset first published.

Main information

Designation
Official statistics
Data provider
Welsh Government
Data source
Road conditions of motorways and A trunk roads
Time period covered
April 1999 to March 2026
Dataset ID
eb556d04-b067-4a5d-81dc-c8ad036b71dc

Overview

Summary of dataset and variables

Skidding resistance relates to wet or damp road surfaces. It is a measure of the road surface condition to the resistance between the vehicle’s tyres and the road when accelerating, braking or cornering. Testing takes place after the road surface has been pre-wetted, as the road surface will exhibit least friction and skid resistance when wet. Testing of dry road surfaces does take place from time to time, however it does not form any part of the routine skid resistance monitoring that takes place on the road network. It is assumed that in dry conditions all clean road surfaces have a high skidding resistance.

Data collection or calculation

Data is collected from SCRIM surveys

Statistical quality

Figures were calculated on a new basis from 2004, which affects all-purpose trunk roads more severely than motorways. Figures relate to road lengths surveyed in the year and in the previous year (for 2006 and earlier years). At or below investigatory level’ does not mean the roads are unsafe; it indicates a need for further investigation to determine the need for maintenance of that section of road. New figures for 2003 were back-calculated to provide a figure equivalent to the new standard used from 2004. In 2007, for the first time all surveyed lengths are taken from the same year and figures are therefore truly representative of that particular year. Also, Lane 1 length of network has been updated.

Related reports

Published by

Organisation
Welsh Government
Contact email
stats.transport@gov.wales