An underride accident occurs when a passenger vehicle collides with a tractor-trailer truck or a single, straight truck, thus running under the truck and possibly shearing off the roof of the passenger car. In many cases, these accidents are fatal to the passengers and driver of the smaller vehicle. In some situations, the occupants of the passenger vehicle may be fortunate enough for the collision to occur near one of the truck’s axles, which would prevent the vehicle from completely sliding under the truck, thus sparing lives.