In this article 8 sections
Uninsured motorist (UM) coverage pays for your injuries when a driver with no insurance, or a hit-and-run driver, causes a crash. Underinsured motorist (UIM) coverage pays when the at-fault driver’s insurance is too small to cover your loss.
The risk is real: the Insurance Research Council estimates 15.4% of U.S. drivers were uninsured in 2023, from 28.2% in Mississippi to 5.7% in Maine (via Triple-I). About 20 jurisdictions require UM coverage. Carrying UM/UIM limits above the state minimum is usually where the protection comes from; ask your insurer what your state allows.
Uninsured driver estimates come from the Insurance Research Council via the Insurance Information Institute; coverage definitions from the NAIC; state requirements from New York DFS and the Illinois Department of Insurance. NextCarReview does not sell insurance, lend money or test financial products; see our sourcing policy.
This is general information, not financial or legal advice; rules vary by state.
Your own liability insurance protects other people from you. Uninsured and underinsured motorist coverage does the reverse: it protects you from drivers who cannot pay for the damage they cause. It is one of the less expensive parts of a policy to raise, yet it is easy to overlook because it only matters when someone else is at fault. This guide covers how it works, how many drivers are uninsured in each state, which states require it, and how to choose limits.
What Is Uninsured and Underinsured Motorist Coverage?
The NAIC defines the two coverages this way: uninsured motorist coverage reimburses you if an uninsured or a hit-and-run driver hits you, and underinsured motorist coverage pays when an at-fault driver does not have enough insurance to fully pay for your loss (NAIC consumer guide). The Insurance Information Institute adds that UM coverage reimburses you, a member of your family or a designated driver (Triple-I).
| Coverage | When it pays | Example |
|---|---|---|
| Uninsured motorist bodily injury (UM) | At-fault driver has no liability insurance, or a hit-and-run | Medical bills and related losses after an uninsured driver runs a red light |
| Underinsured motorist bodily injury (UIM) | At-fault driver’s liability limits are too low | Your injury costs exceed the other driver’s per-person limit |
| Uninsured motorist property damage (UMPD) | Damage to your car by an identified, at-fault uninsured driver | Repairs to your car; offered in some states, often with a deductible |
How Many Drivers Are Uninsured in Your State?
According to the Insurance Information Institute, a 2025 Insurance Research Council study found that 15.4% of motorists, more than one in seven drivers, were uninsured in 2023 (Triple-I facts and statistics). The rate has risen in recent years; in the same 2025 IRC series, the estimate was 12.4% in 2017 and 15.2% in 2022 (Triple-I).
| Highest uninsured rates (2023) | % | Lowest uninsured rates (2023) | % |
|---|---|---|---|
| Mississippi | 28.2% | Maine | 5.7% |
| New Mexico | 24.1% | Utah | 6.2% |
| District of Columbia | 23.1% | Idaho | 6.4% |
| Michigan | 22.3% | Wyoming | 6.7% |
| Tennessee | 21.3% | Montana | 7.2% |
| Missouri | 20.7% | West Virginia | 7.8% |
| Florida | 20.6% | Massachusetts | 7.9% |
| California | 20.4% | New York | 8.6% |
| Colorado | 19.7% | South Dakota | 9.4% |
| Washington | 19.1% | Nebraska | 9.5% |
These are estimates of drivers with no insurance at all. They do not count the larger group who carry only their state’s minimum limits, which is where underinsured motorist coverage comes in.
Which States Require Uninsured Motorist Coverage?
The Insurance Information Institute says uninsured motorist coverage is mandatory in about 20 jurisdictions, and that only a handful of states require underinsured motorist coverage (Triple-I). The NAIC lists UM/UIM as "required by law in some states" (NAIC). Two examples from state regulators:
- New York: all auto policies must include uninsured motorist bodily injury coverage at the same minimums as liability, $25,000 for one person and $50,000 for two or more people per accident (NY DFS).
- Illinois: UM bodily injury coverage is mandated at minimum limits of $25,000 per person and $50,000 per accident; UIM coverage is required if you buy higher UM limits; and insurers must offer UMPD with a maximum deductible of $250 (Illinois Department of Insurance).
If your state does not require it, ask your insurer whether your policy includes it and at what limits. Check your declarations page: if UM/UIM is missing or set at the minimum, you can usually ask to add or raise it at any time.
How Does Underinsured Motorist Coverage Pay?
UIM pays the gap between your losses and what the at-fault driver’s insurance covers, up to your limits, but states calculate that gap in different ways. The Illinois Department of Insurance, for example, describes UIM as paying the difference between your UIM limits and the at-fault driver’s liability limits when theirs are lower (IDOI).
| Illustration (Illinois-style calculation) | Amount |
|---|---|
| Your injury losses | $90,000 |
| At-fault driver’s bodily injury limit (per person) | $25,000 |
| Paid by the at-fault driver’s insurer | $25,000 |
| Your UIM limit | $100,000 |
| UIM available: your $100,000 limit minus their $25,000 | Up to $75,000 |
| UIM payment: $90,000 losses minus $25,000 already paid | $65,000 |
| Same crash with a $25,000 UIM limit | $0 from UIM; $65,000 uncovered |
The example shows why UIM limits equal to the state minimum often add little: if your UIM limit is the same as the other driver’s liability limit, the "difference" can be zero. Triple-I also notes that in states that do not prohibit stacking, UM limits may be multiplied by the number of cars insured on a policy; about half of states prohibit stacking (Triple-I).
How Much Uninsured Motorist Coverage Do You Need?
There is no regulator-set answer, but the NAIC’s general advice applies: state minimum coverages are usually not enough to fully protect you, and higher limits are often available without much increase in premium (NAIC). Practical guidelines:
- Match your liability limits. A common approach is to carry UM/UIM equal to the bodily injury liability limits you buy to protect others.
- Consider who rides with you. UM/UIM typically covers your family and passengers too.
- Check your health and disability coverage. UM/UIM can cover losses health insurance does not, such as lost wages and pain and suffering.
- Look at local risk. In states where one in five drivers is uninsured by IRC estimates, the odds of needing the coverage are higher.
- Ask about UMPD versus collision. If you carry collision, UMPD may duplicate part of it; if you do not, UMPD may be a low-cost way to cover damage by an identified uninsured driver.
When you compare quotes, the NAIC suggests asking each insurer what the deductible is for uninsured and underinsured motorist coverage. Our guide to comparing auto insurance quotes shows how to line up equal coverages, and the auto insurance calculator estimates the effect of changing limits.
What Should You Do If an Uninsured Driver Hits You?
- Call the police and get a report; it documents that the other driver had no insurance or fled.
- Collect the driver’s name, plate and vehicle information, plus witness contacts and photos.
- Notify your insurer promptly. Many policies require prompt notice and, for hit-and-run claims, a police report within a set time.
- Meet your state’s reporting rules. California requires an SR 1 report to the DMV within 10 days when damage exceeds $1,000 or anyone is injured (California DMV).
- Keep records of medical treatment, lost work and repair estimates.
Uninsured drivers face penalties of their own. Triple-I notes they range from fines, which can reach $5,000 for a repeat offense in some states, to license or registration suspension and vehicle impoundment (Triple-I). For serious injuries, our overview of when to talk to an auto accident attorney explains how injury claims usually proceed.
Frequently Asked Questions
What does uninsured motorist coverage pay for?
The NAIC says uninsured motorist coverage reimburses you if an uninsured or hit-and-run driver hits you, and underinsured motorist coverage pays when an at-fault driver does not have enough insurance to fully pay for your loss. It typically covers injuries to you, family members and passengers; damage to your car is a separate coverage in many states.
How many drivers are uninsured?
The Insurance Information Institute, citing a 2025 Insurance Research Council study, reports that 15.4% of motorists, more than one in seven, were uninsured in 2023. Rates ranged from 28.2% in Mississippi to 5.7% in Maine.
Which states require uninsured motorist coverage?
The Insurance Information Institute says uninsured motorist coverage is mandatory in about 20 jurisdictions and that only a handful require underinsured motorist coverage. New York and Illinois are examples: both require uninsured motorist bodily injury coverage at $25,000 per person and $50,000 per accident.
Is uninsured motorist coverage worth it if I have health insurance?
Often yes. Health insurance may not cover lost wages, pain and suffering, or passengers, and it can leave deductibles and copays. Uninsured and underinsured motorist coverage can fill those gaps when the driver who hit you cannot pay.
Does uninsured motorist coverage cover hit-and-run accidents?
Generally yes for injuries. The NAIC and the Illinois Department of Insurance both describe uninsured motorist bodily injury coverage as applying to hit-and-run drivers. Coverage for vehicle damage in a hit-and-run depends on your state and policy; collision coverage may be needed.
⚠️ Professional Notice:
Uninsured motorist rates are Insurance Research Council estimates for 2023 as published by the Insurance Information Institute. UM/UIM rules, stacking and offset methods vary by state and policy.
This is general information, not financial, insurance or legal advice. NextCarReview.com does not receive compensation from any lender, insurer, dealer or warranty company for editorial coverage, and does not rank or recommend specific companies.
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More in this series:
Data Sources and Verification
- Insurance Information Institute: Facts + Statistics, uninsured motorists (IRC 2025 study)
- Insurance Information Institute: Background on compulsory auto and uninsured motorists
- Insurance Information Institute: What is covered by a basic auto insurance policy?
- NAIC: A Consumer’s Guide to Auto Insurance (PDF)
- New York DFS: How much auto insurance must I carry?
- Illinois Department of Insurance: Auto insurance definitions
- California DMV Driver Handbook: SR 1 reporting
Morgan Reyes is the founder and editor-in-chief of NextCarReview, which Morgan launched in August 2024. A 2022 graduate of Columbia University, Morgan is based in New York and writes and edits the site’s reviews, comparisons and buying guides. Morgan does not road-test vehicles. Every article is built from published primary data: EPA FuelEconomy.gov ratings, NHTSA crash ratings, recalls and owner complaints, IIHS results, and manufacturer specifications and pricing, with each figure cited and checked before publication. Contact: admin@nextcarreview.com
