People don’t take whiplash seriously until they suffer one. These injuries are very frequent, every 15 seconds in the United States, and can cause permanent even progressive injury and pain from even a low speed accident. Cars are getting better at protecting you but trucks or cars with trailer hitches can send all of the force in a rear end collision right to your body.
Of great importance in protecting you are the head restraints in your car or truck. Some seats have head rests built in. These are very good at protecting motorists. The adjustable kind MUST be properly adjusted to work well. Place the head rest so the middle of it touches the back of your head, then raise it another inch. The best driving position is with your head 3-4 inches from the head rest. Use them in both the front and back seats.
Please keep in mind that people with long thin necks and people with pre-existing neck problems are most subject to injury. Also people whose neck or body is turned at the time of the accident or suffer an unexpected impact are more likely to be injured.
Good advice is to choose a safe car and drive safely and always wear your seat beat.