This SAE Recommended Practice establishes a procedure for determination of vehicle road load force for speeds between 115 and 15 km/h (71.5 and 9.3 mph). It employs the coastdown method and applies to vehicles designed for on-road operation. The final result is a model of road load force (as a function of speed) during operation on a dry, level road under reference conditions of 20 °C (68 °F), 98.21 kPa (29.00 in-Hg), no wind, no precipitation, and the transmission in neutral.