The average semi-truck can reach up to 70 feet in length. This is much larger than the average sedan or passenger vehicle, which is about 10 to 14 feet long. This difference in size is often a crucial factor in the severity of a truck accident since length and height differences can often impact the gravity of an accident. For example, because a truck typically sits much higher off the ground than a sedan, it can easily override a passenger car and result in the car getting stuck underneath.