本文件描述了一个严格的工程试验程序，该程序利用行业公认的数据收集和统计分析方法来确定道路荷载，并估算重量超过10000磅的卡车和公共汽车的空气动力阻力面积。试验程序可在受控条件下在试验跑道或公共道路上进行，并由大量数据收集和数据分析约束条件支持。估算的空气动力阻力面积结果代表一个- 速度和单偏航角条件。未严格遵循本文所述方法的试验结果不得表示为SAE J2978结果。

This document describes a rigorous engineering test procedure that utilizes industry-accepted data collection and statistical analysis methods to determine the road load and to estimate the aerodynamic drag area of trucks and buses weighing more than 10000 pounds. The test procedure may be conducted on a test track or on a public road under controlled conditions and supported by extensive data collection and data analysis constraints. The estimated aerodynamic-drag-area result represents a single-speed and single-yaw-angle condition. Test results that do not rigorously follow the method described herein shall not be represented as an SAE J2978 result.