Calculation of Local Equilibrium Correction Factors for the 2020 skid resistance surveys

Highways England manages levels of skid resistance on their network (the Strategic Road Network or SRN) by carrying out single annual skid resistance surveys (SASS). This data is used to identify sites where there is a need to undertake an investigation to identify if a resurfacing treatment would be beneficial in mitigating the risk of skidding collisions at the site. In addition, this data feeds into the KPI for Pavement Condition. These surveys are corrected for seasonal variation by the application of correction factors called the “Local Equilibrium Correction Factors” (LECF). The procedure used since 2007 to calculate the LECFs was used again during 2020. This document provides a record of the procedure used to derive the LECFs that have been applied to the 2020 skid resistance survey data.