有两列，On Roadway 和Off Roadway；Off Roadway是NHTSA定义，指的是车跑出路后撞上树墙。。。。

On Roadway 和Off Roadway；

 

Off Roadway是NHTSA定义，指的是车跑出路后撞上树墙。。。。

A run-off-road (ROR) crash occurs when a vehicle in transit   leaves the road and collides with a

tree, a pole, other natural or artificial objects, or overturns on non-traversable terrain. This type of  crash  usually  involves  only  a  single  vehicle.

NHTSA有博士研究这东东

 

https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/811500