Skid Resistance


Skid Resistance of road surfaces can be measured in multiple ways. In the UK three principles are used for traffic speed assessments of skid resistance, sideways force measurement, fixed slip and locked wheel.

Sideways force skid resistance Survey devices

The skid resistance standard, CS 228 (part of the Design Manual for Roads and Bridges or DMRB) specifies that routine surveys of the trunk road network will be undertaken with an accredited sideways force skid resistance survey device. These surveys are conducted at either 50km/h or 80km/h target speeds (depending on the road). The data is then speed corrected to 50km/h before analysis.

These devices employ a test wheel angled to the direction of travel and are described in BS7941-1. The angle of the test tyre forces it to slip against the road surface, allowing the skid resistance of the surface to be assessed through the measurement of forces on the tyre. The Accreditation and QA requirements for these devices are given in the Accreditation and QA specification.

Accreditation_and_QA_of_Sideway-force_Skid_resistance_devices Issue 4.1 Jun 2020

If you are looking for a contractor to carry out skid resistance surveys compliant with CS 228 on your behalf, you may wish to check the list of Sideways force skid resistance survey devices below. On this page you can also find the latest accreditation certificates. In this table machines are referred to as having met criteria if they have met the mandatory criteria as defined in the Accreditation and QA specification for these devices. Some Network Authorities may also require a specific level of performance in some or all of the additional tests. Please see the certificates for more detail on the performance of these devices in these additional tests.

ID Reg plate Operating Company Met criteria Certificate
03 IKZ 2203  DfI Roads  Yes 2023 Skid M03
13 S7 WDM  WDM Ltd  Yes 2023 Skid M13
16 S66 HSL  PTS  No Unassessed
17 S800 WDM WDM Ltd  Yes 2023 Skid M17
19  S900 WDM WDM Ltd  Yes 2023 Skid M19
21 KX07 YXH  Surrey County Council  Yes 2023 Skid M21
22 KX07 YVH PTS Yes* 2023 Skid M22
23 S111 WDM WDM Ltd Yes 2023 Skid M23
24 S12 WDM WDM Ltd Yes 2023 Skid M24
25 S13 WDM WDM Ltd Yes 2023 Skid M25
26 S14 WDM WDM Ltd No Unassessed
28 WX60 AXN TRL (on behalf of National Highways) Yes 2023 Skid M28
29 YD02 XSN PTS Yes 2023 Skid M29
31 S16 WDM WDM Ltd Yes 2023 Skid M31
33 17 2G 1777 PMS Eire Yes 2023 Skid M33
34 49-898P WDM Ltd Yes 2023 Skid M34
35 22 1G 1770 PMS Eire Yes 2023 Skid M35
36 72-805P WDM Ltd No Unassessed
37 S18 WDM WDM Ltd Yes 2023 Skid M37

* This device did not meet the automatic markers criteria for distance (a requirement for systems providing OSGR data) however it did meet the manual markers criteria.

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