ASTM E445/E445M-88(2001)

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

The stopping distance values measured by this test method with the equipment and procedures stated herein do not necessarily agree or correlate directly with other methods of skid-resistance measurements.^{6 ,7} This test method is suitable for research and development purposes, where direct comparison between pavement surfaces are to be made within the same test program.

1.1 This test method covers the measurement of stopping distance on paved surfaces with a passenger vehicle equipped with specified full-scale automobile tires.

1.2 This test method utilizes a measurement of stopping distances representing the non-steady state skid resistance on four locked wheels as the vehicle decelerates over a wetted pavement surface under specified limits of static wheel load and from a desired speed, while the vehicle remains essentially parallel to its original direction of motion.

1.3 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.

1.4 This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety problems associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.