ISO 14794:2011规定了开环测试方法，用于确定制动对重型车辆或重型车辆组合的航向保持和方向行为的影响，当使用以下方法完成制动时 行车制动系统，或 仅限减速器或发动机制动器。 ISO 14794:2011适用于重型车辆，即ISO 3833中定义的商用车辆、商用车辆组合、公共汽车和铰接式公共汽车，涵盖在UNECE（联合国欧洲经济委员会）和EC车辆法规的M3、N2、N3、O3和O4类别中。这些类别适用于最大质量超过3.5吨的卡车和拖车，以及最大质量超过5吨的公共汽车和铰接式公共汽车。

ISO 14794:2011 specifies open-loop test methods for determining the effect of braking on the course-holding and directional behaviour of heavy vehicles or heavy vehicle combinations when braking is accomplished using

• the service-brake system, or
• the retarder or engine brake only.

ISO 14794:2011 is applicable to heavy vehicles, i.e. commercial vehicles, commercial vehicle combinations, buses and articulated buses as defined in ISO 3833, covered by Categories M3, N2, N3, O3 and O4 of UNECE (United Nations Economic Commission for Europe) and EC vehicle regulations. These categories pertain to trucks and trailers with a maximum mass above 3,5 t and to buses and articulated buses with a maximum mass above 5 t.