What Happens If You're Hit by an Uninsured Driver

Uninsured motorist coverage (UM) is a type of auto insurance that pays your medical bills and, in some states, your vehicle repair costs when you're injured by a driver who has no liability insurance. Underinsured motorist coverage (UIM) does the same thing when the at-fault driver has insurance but not enough to cover your damages. Together, UM/UIM coverage is your financial backup plan for the roughly one in seven drivers on the road who either can't or won't carry adequate insurance.

According to a 2025 study by the Insurance Research Council, 15.4% of U.S. motorists were uninsured in 2023. When you add in drivers who are technically insured but carry only state minimum limits, one in three drivers (33.4%) was either uninsured or underinsured. That number has increased by 10 percentage points since 2017.

What happens when the other driver has no insurance

You're stopped at a red light. Someone rear-ends you. Your neck hurts, your bumper is crushed, and when you exchange information, the other driver admits they don't have insurance. Here's what you're facing:

Without UM coverage: You can sue the uninsured driver, but collecting is another story. Someone who can't afford insurance often can't afford to pay a judgment. You're left covering your own medical bills, lost wages, and vehicle repairs out of pocket. Your health insurance may cover some medical costs (minus your health insurance deductible and copays), but it won't cover lost wages, pain and suffering, or car repairs.

With UM coverage: You file a claim with your own insurance company under your uninsured motorist coverage. Your insurer pays your medical bills and compensates you for pain and suffering, up to your UM policy limits. In states that include uninsured motorist property damage (UMPD), your vehicle damage is covered too. The process works a lot like filing a claim against the other driver's insurer, except the claim goes to your own company.

The difference between these two outcomes is the difference between financial recovery and financial hardship.

What happens when the other driver doesn't have enough insurance

This scenario is actually more common than a completely uninsured driver. The at-fault driver has insurance, but their limits are too low to cover your damages.

Say you're in an accident that causes $80,000 in medical bills and the at-fault driver carries the state minimum of $25,000 per person for bodily injury. Their insurance pays their $25,000 limit, and that's it. You're $55,000 short.

Without UIM coverage: You absorb the $55,000 gap. You can sue the at-fault driver for the remaining amount, but again, collecting a judgment from someone who carries minimum coverage is difficult.

With UIM coverage: Your underinsured motorist coverage picks up where the other driver's policy left off. If you carry 100/300 UIM limits, your insurer pays the remaining $55,000 (up to your per-person limit minus what the at-fault driver's policy already paid, depending on your state's offset rules).

How UM/UIM limits work on your Dec page

UM/UIM limits appear on your declarations page in the coverages section, usually shown the same way as your liability limits: as two numbers like 100/300 (per person / per accident) for bodily injury.

A best practice recommended by many insurance professionals: match your UM/UIM limits to your liability limits. If you carry 100/300/100 liability, carry 100/300 UM/UIM. The logic is straightforward. If you think you need $100,000 per person in liability protection against claims you might cause, you need at least that much protection against claims caused by someone else who may have nothing.

Some states also offer uninsured motorist property damage (UMPD), which covers your vehicle damage when the at-fault driver is uninsured. In states without UMPD, your collision coverage handles that (if you have it), subject to your collision deductible.

States where UM/UIM coverage is required

About 21 states and Washington, D.C. require some form of uninsured or underinsured motorist coverage. Requirements vary. Some states mandate bodily injury UM only. Others require both UM and UIM. A few states require the coverage but let you reject it in writing. See our complete state-by-state minimums chart for the rules in your state, and our explainer on no-fault vs. at-fault states to understand how the broader system shapes UM requirements.

Even in states where UM/UIM is optional, your carrier is generally required to offer it to you. If you declined it at some point (possibly without fully understanding what you were declining), it may not be on your policy. Check your Dec page. If you don't see uninsured/underinsured motorist coverage listed, call your agent and ask about adding it.

The states with the most uninsured drivers

Where you live affects your risk. The IRC's 2025 study found that uninsured motorist rates in 2023 ranged from under 6% in states like Maine and Utah to over 28% in Mississippi. Five states had uninsured rates above 20%: Mississippi, New Mexico, Washington D.C., Tennessee, and Michigan.

If you live in a high-UM-rate state and don't carry uninsured motorist coverage, you're playing the odds against yourself.

What UM/UIM costs

UM/UIM is one of the least expensive coverages on your policy relative to the protection it provides. The Insurance Information Institute has reported that the national average cost of UM coverage is roughly $78 per insured vehicle per year. Your actual cost depends on your state, your limits, and your carrier, but for most drivers, adding or increasing UM/UIM coverage adds a modest amount to the total premium.

Compare that to the potential cost of a single accident with an uninsured driver: $20,000 to $100,000 or more in medical bills, lost wages, and vehicle damage. The math is not close.

Hit-and-run accidents

UM coverage also applies to hit-and-run accidents in most states. If a driver hits you and flees the scene, they're treated as an uninsured motorist for coverage purposes. Without UM coverage, you have no way to recover damages from a driver who can't be identified.

This is one of the most commonly overlooked benefits of UM coverage. Hit-and-runs account for roughly 737,000 crashes per year in the United States, according to AAA Foundation for Traffic Safety research.

Frequently asked questions

If I have health insurance, do I still need UM coverage?

Health insurance covers medical treatment, but it won't cover lost wages, pain and suffering, or vehicle damage. UM coverage fills those gaps. It also pays your medical bills first in many states, which means you may not even need to use your health insurance deductible for accident-related care.

Can I sue an uninsured driver?

Yes, but winning a lawsuit and collecting the money are two different things. A driver without insurance often lacks the assets to pay a judgment. UM coverage pays without requiring you to sue anyone.

Does UM/UIM cover my passengers?

In most states, yes. Your UM/UIM coverage extends to passengers in your vehicle at the time of the accident. The specifics depend on your state and your policy language.

What's the difference between "stacking" and "non-stacking" UM/UIM?

In some states, if you insure multiple vehicles, you can "stack" your UM/UIM limits, meaning you multiply the per-vehicle limits by the number of vehicles on your policy. If you have $100,000 UM on a two-car policy in a stacking state, you could have access to $200,000 in UM coverage. Not all states allow stacking, and in states that do, it usually costs more. Check with your agent.