A serious crash can feel confusing fast, especially when the at-fault driver has no insurance or not enough insurance to cover the losses. That is where uninsured motorist (UM) and underinsured motorist (UIM) coverage often enter the picture. These claims can be important because they may open another path to recovery when the other driver’s policy falls short.
In general terms, UM/UIM coverage is designed to protect you, the insured person, when someone else causes the wreck but lacks adequate liability coverage. According to the Insurance Information Institute, 15.4% of U.S. drivers were uninsured in 2023, and the Insurance Research Council reported that 18.0% were underinsured that same year. Put differently, a large share of crashes may involve a driver whose insurance is not enough for the harm caused.
For beginners, the hardest part is often understanding whose insurance pays, when UM/UIM applies, and why these claims can become technical very quickly. In this post you’ll learn what UM and UIM coverage are, how claims usually work, what documents matter, and why many injured people look for legal help when coverage disputes start to develop. If you want a broader overview of how this type of protection fits into serious injury cases, this plain-English breakdown of UM/UIM coverage and recovery issues offers useful background.
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UM stands for uninsured motorist coverage.
UIM stands for underinsured motorist coverage.
The NAIC’s consumer auto insurance resources explain that auto policies commonly include sections for liability coverage, damage to your own vehicle, and uninsured/underinsured motorist coverage. The NAIC Auto Insurance Database Report describes UM coverage as protection for bodily injury caused by an at-fault driver who has no liability insurance, is involved in a hit-and-run, or whose insurer denies coverage or becomes insolvent. The same report explains that UIM coverage applies when the at-fault driver is insured, but the driver’s limits are not adequate to pay all damages in a serious accident.
Here’s the simple version:
These claims are usually made under your own auto policy, even though another driver caused the collision. That can feel backwards at first. But that is the structure of the coverage: you paid premiums for protection in case the other driver did not carry enough.
Serious crashes often generate losses that rise well beyond basic policy limits. Hospital care, surgery, follow-up treatment, physical therapy, lost income, and long-term impairment can make even a “standard” liability policy look very small.
That issue is not theoretical. State minimum limits can be relatively modest. For example, the New York Department of Financial Services explains that New York’s minimum liability limits are often expressed as 25/50/10, meaning $25,000 for bodily injury to one person, $50,000 for bodily injury to multiple people, and $10,000 for property damage. In California, the California Department of Insurance explains that beginning in 2025, standard minimum liability limits increased to 30/60/15. Even with those increases, a crash involving major injuries can exceed those amounts quickly.
At the same time, the injury burden on U.S. roads remains significant. The National Highway Traffic Safety Administration reported an estimated 36,640 traffic fatalities in 2025, following 39,345 fatalities in 2024. Fatalities are only part of the picture; many more people survive with substantial injuries, rehabilitation needs, and wage loss issues. When the at-fault driver carries minimal coverage, UM/UIM can become one of the central insurance issues in the case.
The first place people usually look is the declarations page of the policy. The NAIC explains that the declarations page identifies the policy term, the insured, and the coverage limits. Another NAIC consumer resource on declarations pages notes that this page commonly lists the vehicles, coverages, limits, premiums, and other policy details in one place (NAIC declarations overview).
When reviewing a policy, people often look for entries such as: