What if the person who caused the accident doesn't have enough insurance to fully compensate me or has no insurance at all?

Every insurance policy has underinsurance and uninsured motorist coverage, unless you waive the coverage. Underinsured motorist coverage (UIM) applies when the value of your case exceeds the amount of the other person's insurance. Uninsured motorist coverage (UM), on the other hand, applies when the person who caused the accident had no insurance. In that case, your uninsured motorist coverage compensates you for the damage caused by the other driver. Again, this is coverage for which you have already paid.