SAE J986_201808规定了用于测定车辆总质量额定值小于等于4540 kg的乘用车、多用途车辆和轻型卡车外部声级的试验程序、环境和仪器。该试验程序的特点是具有固定的初始条件，即在试验现场的固定起点处具有规定的初始车速和档位选择。本程序包括车辆的节气门全开加速和节气门关闭减速。根据本文件确定的声级取决于受功率影响的试验车辆的性能- 质量比和动力总成传动比。

SAE J986_201808 establishes the test procedure, environment, and instrumentation for determining the exterior sound level for passenger cars, multipurpose vehicles, and light trucks having a gross vehicle mass rating of 4540 kg or less. The test procedure is characterized by having fixed initial conditions, i.e., an as-specified initial vehicle speed and gear selection at a fixed start point on the test site. Full-throttle acceleration and closed-throttle deceleration of the vehicle are included in this procedure.Sound levels determined in accordance with this document are dependent on the performance capability of the test vehicle, as influenced by power-to-mass ratio and overall powertrain gear ratio.