Uninsured motorist coverage is additional coverage in a policy of insurance on an automobile which provides that if the owner (or a passenger) of the automobile is injured by a negligent driver of another vehicle who does not have liability insurance, then the insurance company will pay its insured's actual damages.
Uninsured motorist bodily injury coverage is available in some states, where it's often mandatory. This kind of auto insurance coverage pays for your medical expenses, lost wages, and other general damages when you or your passengers are injured in an accident caused by a driver who has no car insurance. Uninsured motorist coverage also pays for injuries sustained in hit-and-run accidents. The amount covered by uninsured motorist bodily injury is capped at the limit you choose when you buy your auto insurance policy.
Uninsured motorist coverage is distinguished from underinsured motorist coverage, which is used to protect you from losses when the other vehicle's policy limit is inadequate to pay for all your damages.
Definitions vary by jurisdiction, but the following is an example of a statute defining an uninsured motorist:
"Uninsured motor vehicle" is a vehicle other than a motor vehicle owned by or furnished for the regular use of the named insured, the spouse of the named insured, residents of the same household, or the relative of either, as to which there is:
A motor vehicle shall be deemed to be uninsured if the owner or operator of the motor vehicle is unknown. In those cases, recovery under the endorsement or provisions shall be subject to the conditions set forth in subsections (c) through (j) of this Code section and, in order for the insured to recover under the endorsement where the owner or operator of any motor vehicle which causes bodily injury or property damage to the insured is unknown, actual physical contact must have occurred between the motor vehicle owned or operated by the unknown person and the person or property of the insured. Such physical contact shall not be required if the description by the claimant of how the occurrence occurred is corroborated by an eyewitness to the occurrence other than the claimant."