ISO International Standard

Road vehicles — Measurement of road surface friction

This International Standard specifies test methods for determining the characteristic longitudinal friction force

values of paved surfaces using either a standard reference test tyre or the tyre of a vehicle under test. General test

procedures and their validity are presented for determining peak- and slide-braking coefficients on actual test

surfaces, where the surface conditions are determined and controlled by the user at the time of testing. Test and

test-surface condition documentation procedures and details are also specified.

The purpose of this International Standard is to provide for the harmonization of results of testing on different test

tracks. The values measured with standard reference test tyres (SRTT) are intended to form standard reference

numbers indicating the friction properties of test tracks and road surfaces that are representative for passenger car


Certain of the methods may also be suitable for measuring the friction properties for a specific test car tyre on the

test track.

The values quantify the peak-, near-peak or slide-braking coefficients at the time of test and do not necessarily

represent fixed values.

The values measured with reference tyres are intended as reference numbers indicating certain friction properties

of test tracks and road surfaces.

This International Standard does not purport to address all the safety problems associated with its use. It is the

responsibility of the user to consult and establish appropriate safety and health practices and determine the

applicability of regulatory limitations prior to use.

NOTE 1 Friction is affected by many variables such as environmental conditions, usage, age and surface contamination.

Measured values will change when any of these conditions significantly changes.

NOTE 2 The measured braking coefficient values obtained with the procedures stated in this International Standard may not

necessarily agree or correlate directly with those obtained by other surface coefficient measuring methods.

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