Uninsured motorist coverage and underinsured motorist coverage are two of the more confusing types of car insurance coverage. In some states these coverages are required, so you have no choice but to add them to your car insurance policy. In other states the coverage is optional, but it doesn’t cost very much, and it’s generally worthwhile. Here’s what you need to know to decide whether to buy this protection. What is uninsured motorist coverage? Uninsured motorist coverage helps pay for any injuries caused to you or your passengers in an accident involving an uninsured driver, or a hit and run.