Fatigued driving often results in head-on collision accidents. When people fall asleep at the wheel, they will often drift into the opposite lane of traffic and hit another vehicle head-on. Other truck accident types include ‘jackknifing,’ which happens when a driver breaks too quickly and the trailer swings out from behind the tractor at a 90-degree angle. This can happen when a driver’s judgment and reflexes are impaired by fatigue.  Another consequence of slamming on the breaks is ‘underride accidents.’ These occur when a truck stops short and a smaller vehicle collides with the truck and slides underneath the trailer itself.