A significant number of the fatal motor vehicle accidents which happen on American roads each year involve large trucks. The size of the vehicle is largely responsible for the number of fatalities which occur in any truck accident involving other cars. Most fatal truck accidents happen when cars overtaking other cars on rural roads fail to judge the distance of an oncoming truck and collide with the truck head-on. Other accidents may involve jack-knifing, where trucks slide on ice or wet roads, causing other vehicles to crash into the side of the vehicle. In both cases, it is usually the passengers in other vehicles involved in the accident which are killed or injured. Large trucks are more likely to be involved in multi-vehicle accidents causing fatalities than normal family motor cars are. Fatal truck accidents are very rarely related to alcohol and drink driving, but instead are usually caused by driver error of either the truck or another vehicle. Fatal truck accidents are a particularly high risk in rural areas and during weekends.