ASTM E445/E445M-15(2019)

4.1 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.

4.2 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.5^,6 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 SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the standard.

1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.