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.
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.
Skidding resistance of all Trunk Roads in Wales
Length of network