ANSI/ASABE S648的本部分提供了规范性参考，并确定了与牵引车和牵引列车制动相关的最低要求。这些要求和最低性能标准适用于最大设计地面速度大于6 km/h（3.7 mile/h）的牵引车和牵引列车的运行和停车。

This part of ANSI/ASABE S648 provides normative references and establishes the minimum requirements related to braking of towed vehicles and towed vehicle trains.These requirements and minimum performance criteria are directed to the operation and parking of towed vehicles and towed vehicle trains having a maximum design ground speed greater than 6 km/h (3.7 mile/h).