This type of coverage is designed to pay for damages if you’re hit by a driver with no insurance or not enough coverage with their policy. It prevents you from paying out of pocket the difference between the other party’s insurance and the cost of medical care. This type of coverage kicks in if you’re hit by a driver who leaves the scene. Since you can’t get the expenses paid by their insurance, you would have to rely on the amount of coverage you have under this part of the policy. Most states require either uninsured or underinsured motorist coverage, and many states require both. They may have a minimum, but you can always add more if you feel that you want more protection.