Uninsured or underinsured (UM) motorists coverage pays for your injuries when the person at fault for the accident has inadequate insurance to pay for your medical bills and other costs associated with your injury. UM coverage also applies if you are the victim of a hit and run driver. Usually limited to bodily injury, this type of insurance does not cover damage to your vehicle or other property. For this type of protection from uninsured or underinsured motorists, you must have collision coverage on your policy.