The knowledge of vehicle stopping distance or deceleration serves as an additional tool in characterizing the pavement surface skid resistance. When used in conjunctionwith other physical and chemical tests, the skid resistance values derived from these test methods may determine the suitability and adequacy of paving materials or finishing techniques. Improvements in pavement maintenance practices and schedules may result from use of these test methods.

The stopping distance or deceleration values measured by these two test methods with the equipment and procedures stated herein do not necessarily agree or correlate directly with other methods of skid-resistance measurements. These test methods are suitable where direct comparison between pavement surfaces are to be made within the same test program.

1.1 These test methods cover the measurement of skid resistance on paved surfaces with a passenger vehicle equipped with specified full-scale vehicle tires and using the diagonal braking mode. These test methods include the following:

1.1.1 Full-Stop Method This represents the nonsteady-state skid resistance on two diagonally locked wheels, as the vehicle decelerates over a wetted pavement surface under specified limits of static wheel load and from a desired speed. The vehicle shall remain essentially parallel to its original direction of motion.

1.1.2 Pulse-Braking MethodThe deceleration resulting from momentary diagonal wheel lockup (pulse braking) is measured. The vehicle decelerates over a wetted pavement surface under specified limits of static wheel load and at a desired speed. The vehicle shall remain essentially parallel to its original direction of motion.

1.2 The values stated in either inch-pound units or SI units are to be regarded separately as standard. Within the text, the SI units are shown in brackets. The values stated in each system are not exact equivalents: therefore, each system must be used independently of the other. Combining values from the two systems may result in nonconformance with the specification.