AASHTO TP 143-21

This test method covers the measurement of the sideway-force friction of paved surfaces using a tire mounted at 20 degrees, herein referred to as the device.
This test method utilizes the measurements obtained by a device, containing one freely rotating test wheel angled at 20 degrees to the direction of motion, and operated over a pavement surface at operating speed while the test wheel is under a vertical load. The test equipment has been built onto a number of different vehicle chassis and functions independently of vehicle choice. This method provides data of the sideway-force friction (and other data) along the whole length of the pavement surface being tested. The data are intended for use in comparing certain frictional properties of a pavement relative to those of other pavements or for evaluating changes in these frictional properties of a pavement with the passage of time. The data are insufficient to determine the distance required to stop a vehicle on either a wet or a dry pavement.