Making a U-turn in a car or SUV involves dangers that do not necessarily exist when a driver makes a regular turn. For example, the driver making the U-turn may have to cross multiple lanes of traffic with other vehicles approaching the turning car from two different directions. Also, people on side streets may be trying to turn onto the road just when the other vehicle is in the middle of the U-turn, which can create an instant collision.
The vast majority of motorcyclists are careful riders who properly share the road with cars and trucks. However, despite the best efforts of motorcyclists, sometimes they suffer serious injuries because of other motorists' actions.