Uninsured Motorist Coverage: How It Works and Whether You Need It

Uninsured motorist coverage pays for your injuries, and in some states your car's damage, when an at-fault driver has no insurance or flees the scene. Its companion, underinsured motorist coverage, pays when the at-fault driver's limits are too low. Some states require it; most let you decline it in writing.

You cannot control whether the driver who hits you carries adequate insurance. This coverage is how you protect yourself anyway. Below, we explain what each part covers, how it differs from other coverages, and how to choose limits.

What does uninsured motorist coverage cover?

Uninsured and underinsured motorist coverage come in several pieces. Your policy may include some or all of them, depending on your state and choices.

UM coverage generally protects you as a driver or passenger in your own car, and often when you are a pedestrian or riding in someone else's car. That broad reach is one reason it is worth understanding. For a view of how it fits with everything else in a policy, see our overview of car insurance coverage types.

Uninsured vs. underinsured motorist coverage

The two are easy to confuse:

• Uninsured (UM): the at-fault driver has no liability insurance at all, or cannot be identified.
• Underinsured (UIM): the at-fault driver has insurance, but not enough.

Underinsured claims are more common than many people realize. State minimum liability limits in many states are low compared with the cost of a hospital stay, surgery, or months of lost income. If a driver carrying only a minimum policy seriously injures you, their coverage could run out quickly.

Is uninsured motorist coverage required?

Rules vary by state. Broadly, states fall into three groups:

• Required: the state mandates UM, UIM, or both as part of every auto policy.
• Must be offered: insurers must include it unless you reject it in writing, usually on a signed form.
• Optional: you may add it if you choose.

Required minimum limits also vary. Because the rules change and differ widely, check your state insurance department's website or ask your agent what applies where you live.

How uninsured motorist coverage differs from other coverage

It is fair to ask whether you need UM if you already have health insurance and collision coverage. Each fills a different gap:

• Health insurance pays medical bills but not lost wages or pain and suffering, and may leave deductibles and copays.
• Personal injury protection or medical payments, where available, cover some medical costs regardless of fault, but usually with modest limits.
• Collision repairs your car regardless of fault, but you pay the deductible. In some states UMPD comes with a lower deductible or none.
• Your liability coverage protects other people when you are at fault. It does nothing for your own injuries.

A further difference: UM and UIM typically follow you, not just your car. In many policies they cover you and household family members as pedestrians, cyclists, or passengers in someone else's vehicle. Health insurance may cover some of the same medical bills, but it will not replace a lost paycheck or compensate for long-term pain, which is often where the largest costs in a serious crash come from.

UM and UIM are the coverages designed to put you where you would be if the at-fault driver had carried good insurance. Our explainer on liability vs. full coverage covers how liability and physical damage coverages fit together.

How much uninsured motorist coverage should you carry?

A common guideline is to match your UM/UIM limits to your own liability limits. The logic is simple: you have decided how much protection other people deserve if you hurt them, so give yourself the same.

Consider higher limits if:

• You have a high-deductible health plan or limited health coverage
• You lack disability insurance and depend on your income
• You regularly carry passengers, such as children or carpool riders
• You drive often in areas where many drivers are uninsured

Consider whether you need UMPD if:

• Your car is older and you have dropped collision, in which case UMPD may be your only protection for vehicle damage from an uninsured driver
• You carry collision and are comfortable paying its deductible

How to file an uninsured motorist claim

If you are hit by an uninsured or unidentified driver:

1. Call police and get a report, especially for a hit-and-run.
2. Collect what you can: plate number, photos, witness names.
3. Seek medical care and keep records.
4. Notify your insurer promptly; policies often set short deadlines for hit-and-run reports.
5. Keep documentation of lost wages and out-of-pocket costs.

Your insurer effectively steps into the other driver's shoes, which means it will evaluate fault and damages. For the broader claims process and its effect on premiums, see our guide to car insurance after an accident.

The bottom line

Uninsured and underinsured motorist coverage protect you from other drivers' decisions to carry no insurance or too little. It is often inexpensive relative to the protection it offers. Check your declarations page to confirm you have it, consider matching it to your liability limits, and learn your state's rules so you know exactly what is covered.