What Is Uninsured and Underinsured Motorist Coverage?

Uninsured and underinsured motorist coverage protects you when the driver who caused the accident has no insurance, not enough insurance, or sometimes cannot be identified after a hit-and-run.

That is the plain version.

Your liability insurance protects other people when you cause harm. Uninsured and underinsured motorist coverage protects you, your passengers, and sometimes your vehicle when someone else causes harm but does not have enough coverage to pay for it.

The catch is that this coverage varies a lot by state and policy. Some states require it. Some require insurers to offer it. Some let you reject it in writing. Some policies cover bodily injury only. Some also include property damage. The details matter, because this is one of those coverages people do not think about until the other driver says, “I do not have insurance.”

The problem this coverage solves

Imagine you are stopped at a red light. Another driver hits you from behind. Your car is damaged, your back hurts, and you miss work for medical appointments.

Now imagine the driver who hit you has no auto insurance.

That is not your fault, but it is suddenly your problem.

You can try to collect money from the driver directly, but if someone could not afford or did not buy insurance, they may not have enough cash or assets to pay your medical bills, lost wages, pain, vehicle damage, or other costs. A legal claim may still be possible, but collecting is another issue.

This is where uninsured motorist coverage can matter.

NAIC explains that uninsured and underinsured motorist coverage helps cover costs if the insured driver is injured by someone who lacks insurance or has insufficient coverage. NAIC also describes underinsured motorist coverage as paying claims when the at-fault driver does not have enough insurance to pay for your loss fully.

In other words, it is backup protection for someone else’s insurance failure.

Uninsured vs underinsured motorist coverage

These two terms sound similar, but they solve slightly different problems.

Uninsured motorist coverage

Uninsured motorist coverage may apply when the at-fault driver has no liability insurance.

It may also apply in some hit-and-run situations, depending on your state and policy. If the driver cannot be identified, there may be no at-fault driver’s insurance company to collect from. Your uninsured motorist coverage may become the policy section you look to.

NAIC says uninsured motorist coverage can provide coverage for injury or property damage if you are injured by a hit-and-run driver or a driver who does not have auto liability insurance.

Underinsured motorist coverage

Underinsured motorist coverage may apply when the at-fault driver has insurance, but their limits are too low to cover the full loss.

For example, suppose another driver causes a serious accident and has only $25,000 of bodily injury liability coverage. Your medical bills, lost wages, and other damages are $90,000. The at-fault driver has insurance, but not enough.

That is an underinsured motorist problem.

Your underinsured motorist coverage may help with the gap, up to your policy limits and subject to state law and policy rules.

The easiest way to remember it

Use this simple test:

• Uninsured: The at-fault driver has no insurance, or there is no identifiable driver in some hit-and-run cases.
• Underinsured: The at-fault driver has insurance, but their limits are too low.

Both are about the same uncomfortable situation: someone else caused the accident, but their insurance is not enough to make you financially whole.

What uninsured motorist bodily injury may cover

Uninsured motorist bodily injury coverage is often written as UMBI.

This is the part that may help pay for injury-related costs when an uninsured driver causes an accident. Depending on the policy and state, it may protect you, family members in your household, and passengers in your vehicle.

Costs UMBI may help with

• Medical bills
• Lost wages
• Pain and suffering
• Funeral expenses
• Injury-related damages for passengers
• Some injuries as a pedestrian or cyclist, depending on policy and state rules

This is not the same as collision coverage. UMBI is about injuries, not fixing your car.

It is also not the same as health insurance. Health insurance may help with medical bills, but it usually does not replace lost wages, pay pain and suffering, cover every passenger in your car, or handle the full legal value of an injury claim. It may also come with deductibles, copays, coinsurance, networks, and out-of-pocket costs.

That is why people with health insurance may still consider uninsured motorist bodily injury coverage.

What underinsured motorist bodily injury may cover

Underinsured motorist bodily injury coverage is often written as UIMBI.

This coverage may help when the at-fault driver’s bodily injury liability limits are too low to cover your injury claim.

A simple UIMBI example

Suppose your damages from an accident are $100,000.

The at-fault driver has $25,000 of bodily injury liability coverage.

Your underinsured motorist limit is $100,000 per person.

In a simple version, the at-fault driver’s insurer may pay $25,000, and your UIM coverage may be considered for the remaining gap, subject to policy wording, state rules, offsets, and limits.

That last sentence matters.

Underinsured motorist claims are not always as simple as “my limit minus their limit.” Some states and policies use offset rules. Some use different approaches to how limits apply. Some require certain steps before you settle with the at-fault driver’s insurer.

Do not settle an injury claim with the at-fault driver’s insurer without checking your own policy and talking to your insurer first.

What uninsured motorist property damage may cover

Uninsured motorist property damage is often written as UMPD.

This coverage may help pay for damage to your vehicle or other property when an uninsured driver causes the accident. It is not available in every state, and rules vary.

Some states allow UMPD. Some require it. Some do not offer it. Some restrict when it applies, especially in hit-and-run situations where the other driver is not identified.

NAIC notes that uninsured motorist coverage can include injury or property damage protection if you are injured by a hit-and-run driver or a driver with no auto liability insurance. But you still need to check your own state and policy because uninsured motorist property damage rules are not identical everywhere.

UMPD vs collision coverage

UMPD and collision coverage can overlap in a reader’s mind because both may involve damage to your own car.

But they are not the same.

Collision coverage helps repair or replace your own car after a covered collision, regardless of who caused the accident, subject to your deductible and policy terms.

UMPD may help when an uninsured driver damages your car, subject to state and policy rules.

If you already have collision coverage, UMPD may be less important for vehicle repairs, depending on the deductible and how the policy works. If you do not have collision coverage, UMPD may be more interesting, but only if it is available and fits your situation.

This is a good question for your agent:

“If an uninsured driver hits my car, would I use collision, uninsured motorist property damage, or both? What deductible applies?”

What underinsured motorist property damage may cover

Underinsured motorist property damage is less straightforward because it is not handled the same way everywhere.

In some states and policies, underinsured motorist property damage may help when the at-fault driver has some property damage liability coverage but not enough to repair or replace your vehicle.

In other places, underinsured motorist coverage may be mainly or only about bodily injury.

This is why policy wording matters.

Do not assume “UM/UIM” automatically covers your car. It may be bodily injury coverage only. Your declarations page should separate the coverage sections and limits.

How the limits usually appear

Uninsured and underinsured motorist bodily injury limits often look similar to liability limits.

You may see numbers such as:

• $25,000 per person / $50,000 per accident
• $50,000 per person / $100,000 per accident
• $100,000 per person / $300,000 per accident
• $250,000 per person / $500,000 per accident

The first number is usually the maximum for one injured person. The second number is usually the maximum for all injured people in one accident.

So if your UM bodily injury limit is $100,000 per person and $300,000 per accident, one injured person may have up to $100,000 of protection, while all covered injured people in the accident may be limited to $300,000 total.

That is the rough idea.

Always confirm the exact wording.

Why matching your liability limits can make sense

Many people carry higher liability limits because they want to protect others, satisfy lender or umbrella requirements, or protect their own assets if they cause an accident.

It can also make sense to consider similar UM/UIM limits for yourself.

If you think $100,000 or $300,000 is a reasonable amount of protection when you hurt someone else, ask why you would want much less protection when someone else hurts you and has no money or coverage.

That does not mean everyone can afford the highest limits.

But it is worth pricing.

Why state rules matter so much

Uninsured and underinsured motorist coverage is one of the least “one-size-fits-all” parts of auto insurance.

Rules vary by state. Insurers may be required to include it, required to offer it, allowed to offer it, or allowed to let you reject it. Rejection may need to be in writing. Some states require uninsured motorist bodily injury but not property damage. Some handle underinsured motorist coverage differently from uninsured motorist coverage.

NAIC says auto insurance requirements vary by state and that policies can include liability, medical payments, uninsured or underinsured motorist coverage, and coverage for damage to your auto. Its consumer shopping tool also notes that uninsured and underinsured motorist coverages can vary by state or insurer.

This is why an internet answer should not be your final answer.

Use it to understand the coverage. Then check your state rules and your own declarations page.

How UM/UIM differs from liability insurance

Liability insurance pays other people when you cause a covered accident.

UM/UIM coverage protects you when someone else causes a covered accident but has no insurance or too little insurance.

That difference is easy to miss because both are injury-related coverages in an auto policy.

Example: you cause the accident

You run a stop sign and hit another car. The other driver is injured.

Your bodily injury liability coverage may help pay the other driver’s injury claim, up to your limits.

Your UM/UIM coverage is not for that situation because the problem is not an uninsured driver hurting you. The problem is you causing injury to someone else.

Example: someone else causes the accident

Another driver runs a stop sign and hits you. You are injured. The driver has no insurance.

Your bodily injury liability coverage does not pay you for your injuries. That coverage protects other people from your legal responsibility.

Your uninsured motorist bodily injury coverage may be the coverage that matters.

This is why relying only on liability coverage can leave you exposed.

How UM/UIM differs from medical payments or PIP

Medical payments coverage, often called MedPay, and personal injury protection, often called PIP, can help with medical expenses after an accident, depending on the state and policy.

But they are not the same as uninsured or underinsured motorist coverage.

PIP and MedPay may pay regardless of who caused the accident, subject to policy rules. UM/UIM focuses on the other driver’s lack of insurance or lack of enough insurance.

Also, PIP and MedPay limits may be much smaller than a serious injury claim.

For example, you might have $5,000 of MedPay and $100,000 per person of uninsured motorist bodily injury. Those are very different amounts of protection.

Do not assume one makes the other unnecessary.

How UM/UIM differs from collision coverage

Collision coverage is about your vehicle damage after a crash.

UM/UIM bodily injury is about your injury damages when the at-fault driver has no insurance or not enough insurance.

Uninsured motorist property damage, if available, may help with vehicle damage caused by an uninsured driver. But collision is usually broader because it can apply to covered collision damage even if the other driver is insured, uninsured, unknown, or if you hit an object.

Here is the practical question:

If an uninsured driver totals my car, what policy section pays?

The answer depends on whether you have collision coverage, whether you have UMPD, what your state allows, what deductibles apply, and how your insurer handles the claim.

Ask before you need it.

How hit-and-run claims may work

Hit-and-run accidents can be especially frustrating because there may be no at-fault driver to identify.

In some states and policies, uninsured motorist coverage may apply to hit-and-run injury claims. Property damage claims may have stricter rules. Some policies may require physical contact with the other vehicle. Some may require a police report. Some may have notice deadlines.

This is not something to figure out casually later.

After a hit-and-run, do these quickly

• Move to safety if possible.
• Call the police and file a report.
• Get medical help if needed.
• Take photos of the scene and damage.
• Write down the time, location, weather, and what happened.
• Look for witnesses.
• Ask nearby businesses or homes about camera footage.
• Notify your insurer quickly.
• Do not repair the vehicle before documenting the damage.

The police report and early documentation can matter because insurers need evidence that a hit-and-run actually occurred.

Waiting can make the claim harder.

A simple uninsured driver example

Let’s put numbers on it.

You are hit by an uninsured driver. Your injuries and related damages are valued at $80,000. You have uninsured motorist bodily injury coverage of $100,000 per person.

If the claim is covered and approved, your own insurer may pay covered damages up to the policy limit, subject to the policy and state rules.

If you had no uninsured motorist coverage, you may have to rely on health insurance, your own savings, a lawsuit against the driver, or other coverage. That may leave gaps.

The problem is not only the medical bill.

It may be lost income, follow-up care, deductibles, copays, pain, long-term symptoms, and the time it takes to recover.

A simple underinsured driver example

Now imagine the at-fault driver has insurance, but only $25,000 of bodily injury liability coverage.

Your damages are $120,000.

The at-fault driver’s insurer pays $25,000. You have $100,000 per person in underinsured motorist coverage.

Depending on your state and policy, your UIM coverage may help with part of the remaining loss. But the exact calculation can depend on offset rules and policy language.

This is why serious injury claims need careful handling.

Before signing a release or accepting a settlement from the at-fault driver’s insurer, call your own insurer and ask what steps are required to preserve an underinsured motorist claim.

Does UM/UIM cover pain and suffering?

It can, depending on the policy, state rules, and claim facts.

Uninsured and underinsured motorist bodily injury coverage is often designed to stand in the place of the at-fault driver’s missing or inadequate liability coverage. That can mean it may cover damages beyond medical bills, such as lost wages and pain and suffering, if those damages are covered and proven under the policy and law.

But do not assume every cost is automatically paid.

You still need to prove the injury, damages, cause of loss, coverage trigger, and claim value.

Does UM/UIM cover passengers?

It often can, but the details depend on the policy.

Uninsured motorist bodily injury coverage may protect you, family members in your household, and passengers in your insured vehicle. But policies can define “insured person” differently.

If you regularly drive children, relatives, friends, coworkers, or carpool passengers, this coverage deserves attention.

A serious accident can injure more than one person. That is where the “per accident” limit matters.

Does UM/UIM cover you as a pedestrian or cyclist?

Sometimes, yes.

Many auto policies may extend uninsured or underinsured motorist bodily injury coverage to you as a pedestrian or cyclist if you are hit by an uninsured or underinsured driver, but this depends on state law and policy wording.

This is worth checking if you walk, run, bike, or have children who walk or bike near traffic.

Ask your insurer directly:

“Does my UM/UIM bodily injury coverage apply if I am hit as a pedestrian or cyclist?”

Do not guess.

Is this coverage required?

It depends on your state.

Some states require uninsured motorist coverage. Some require both uninsured and underinsured motorist coverage. Some require insurers to offer it, but let drivers reject it. Some require rejection in writing. Some treat property damage differently from bodily injury.

NAIC explains that the type and amount of required auto insurance varies by jurisdiction, even though liability insurance is compulsory in most jurisdictions.

The safest move is to check your state insurance department or ask your insurer what is required, offered, and rejectable where you live.

If you reject coverage, keep a copy of the rejection form and make sure you understand what you are giving up.

Is uninsured and underinsured motorist coverage worth it?

For many drivers, it is worth pricing seriously because it protects against a risk you do not control.

You can drive safely. You can carry good liability limits. You can keep your car maintained. None of that forces the driver behind you to have insurance.

The Insurance Information Institute says uninsured and underinsured motorist coverage reimburses policyholders in accidents involving uninsured, underinsured, or hit-and-run drivers. It also notes that uninsured motorist rates are measured using injury claims involving uninsured drivers compared with injury claims involving insured drivers.

The exact value depends on cost, state rules, your other coverage, your health insurance, your passengers, your assets, and how much financial risk you can carry yourself.

It may be more worth considering if

• You drive often.
• You commute in heavy traffic.
• You drive family members or passengers regularly.
• Your state has a higher uninsured driver problem.
• You do not want to rely only on health insurance after a crash.
• You have limited savings.
• You cannot afford weeks or months of lost income.
• You want protection as a pedestrian or cyclist, if your policy includes that.
• You already carry solid liability limits and want similar protection for yourself.

It may be less important if

• You rarely drive and have strong savings.
• Your state already requires enough coverage for your situation.
• You have other coverage that fills some gaps, though this should be checked carefully.
• The available UM/UIM options are very limited or expensive compared with your risk.

I would still price it before rejecting it.

Sometimes the cost difference is smaller than people expect. Sometimes it is not. The quote tells you.

How much coverage should you carry?

There is no one correct number for everyone.

A practical starting point is to look at your bodily injury liability limits, then consider matching your uninsured and underinsured motorist bodily injury limits if your state and insurer allow it.

For example, if you carry $100,000 per person and $300,000 per accident in bodily injury liability, ask what it would cost to carry the same UM/UIM bodily injury limits.

Then compare lower and higher options.

Questions that affect the limit

• How much would a serious injury affect your income?
• How strong is your health insurance?
• How high are your health deductibles and out-of-pocket costs?
• Do you regularly carry passengers?
• Do you have family members in your household covered under the policy?
• Do you bike or walk near traffic often?
• How much savings could you use after an accident?
• Would your current limit cover more than a minor injury?

Low limits may satisfy a requirement, but they may not solve a serious injury problem.

Price several options before deciding.

Stacked vs unstacked coverage

Stacking is a state-specific feature that may let you combine uninsured or underinsured motorist limits across multiple vehicles or policies.

For example, if you have two vehicles with $50,000 of UM coverage each, stacking might allow a higher available limit in some situations, depending on state law and policy wording.

Unstacked coverage does not combine limits in the same way.

This can sound like a small detail, but it can matter in a serious injury claim.

Questions to ask about stacking

• Is stacking allowed in my state?
• Is my policy stacked or unstacked?
• Does stacking apply to UM, UIM, or both?
• Does it apply across vehicles on one policy?
• Does it apply across multiple policies?
• How much extra does stacking cost?
• What happens if I reject stacking?

Do not assume stacking exists just because you have more than one car.

It has to be allowed and included.

Common exclusions and limits to watch

UM/UIM coverage has rules.

Do not assume it applies to every situation involving an uninsured person.

Possible restrictions may involve

• Hit-and-run reporting requirements
• Physical contact requirements for some hit-and-run claims
• Notice deadlines
• Excluded vehicles
• Using a vehicle for business, delivery, or rideshare without proper coverage
• Settling with the at-fault driver without insurer consent
• Offset rules
• Policy definitions of insured persons
• Non-owned vehicles
• Motorcycles, scooters, or recreational vehicles
• Intentional acts
• Workers’ compensation overlaps

You do not need to memorize every exclusion.

You do need to know that the coverage is not automatic in every scenario.

Read the UM/UIM section before you rely on it.

How to file a UM or UIM claim

The process depends on the insurer and state, but the basic steps are similar.

After the accident

• Call the police, especially if the other driver is uninsured, leaves the scene, or refuses to share information.
• Get medical help if you may be injured.
• Exchange information if the other driver is present.
• Take photos of the vehicles, scene, license plates, damage, and road conditions.
• Get names and contact details from witnesses.
• Notify your insurer promptly.
• Keep medical records, bills, repair estimates, wage loss records, and communication from insurers.

If the other driver has insurance but low limits, tell your insurer early that a UIM claim may be possible. Your policy may have procedures you must follow before accepting the at-fault driver’s settlement.

During the claim

Your own insurer may investigate the accident, confirm the other driver’s insurance status or limits, review fault, evaluate your injuries or damage, and decide whether the UM/UIM coverage applies.

This can feel strange because your own insurer is now handling a claim where you are asking them to pay.

Be organized.

Keep records. Get claim numbers. Write down who you spoke with and when. If injuries are serious, consider getting qualified legal advice before signing releases or settlements.

What to ask your insurance agent

Use plain questions.

• Do I have uninsured motorist bodily injury coverage?
• Do I have underinsured motorist bodily injury coverage?
• Are my UM/UIM limits the same as my bodily injury liability limits?
• Do I have uninsured motorist property damage?
• Does this coverage apply to hit-and-run accidents?
• Does it cover me as a pedestrian or cyclist?
• Does it cover passengers in my car?
• Is there a deductible for UMPD?
• How does this coverage interact with collision?
• How does it interact with PIP or MedPay?
• Does my state allow stacking?
• Is my coverage stacked or unstacked?
• What happens if I reject this coverage?
• How much would higher limits cost?
• What would make a UM/UIM claim denied?

If the answer is vague, ask for the policy section in writing.

Insurance memory gets fuzzy fast. Documents matter.

What to check on your declarations page

Your declarations page is the policy summary. It should show the major coverage sections, limits, deductibles, vehicles, drivers, policy period, and premium.

Look for lines such as:

• Uninsured motorist bodily injury
• Underinsured motorist bodily injury
• Uninsured motorist property damage
• UM/UIM bodily injury
• UMPD
• Stacked or non-stacked UM
• Rejected UM coverage

Also compare the UM/UIM limits with your bodily injury liability limits.

If you have strong liability limits but very low uninsured motorist limits, ask why.

Common mistakes to avoid

Assuming every driver has enough insurance

Many drivers do not. Some have no insurance. Some carry only minimum limits. Minimum limits can be much lower than the cost of a serious injury accident.

Thinking your liability coverage protects you

Your liability coverage protects other people when you cause a covered accident. It does not pay your injury claim when an uninsured driver hits you.

Assuming health insurance is enough

Health insurance may help with medical bills, but it does not necessarily cover lost wages, pain and suffering, passengers, or every out-of-pocket cost. It also does not fix your car.

Rejecting coverage without pricing it

If your state lets you reject UM/UIM coverage, do not reject it just to save money until you know the actual savings and the risk you are keeping.

Ignoring property damage

UMBI and UIMBI focus on injuries. If you are worried about vehicle damage, ask about collision coverage and uninsured motorist property damage where available.

Settling too quickly

If the at-fault driver is underinsured, settling with their insurer may affect your ability to use your own UIM coverage. Call your insurer before signing anything.

Not documenting a hit-and-run

A hit-and-run claim can be harder without a police report, photos, witnesses, and prompt notice to your insurer.

A quick decision table

Situation	Coverage that may matter	What to check
Uninsured driver injures you	Uninsured motorist bodily injury	Per person and per accident limits
Driver has insurance but low injury limits	Underinsured motorist bodily injury	Offset rules and settlement requirements
Uninsured driver damages your car	Collision or uninsured motorist property damage	Deductible, availability, and state rules
Hit-and-run driver injures you	Uninsured motorist bodily injury may apply	Police report, policy rules, and deadlines
You are hit while walking or biking	UM/UIM bodily injury may apply	Whether your policy covers you outside the car
Multiple cars on policy	Stacked UM/UIM may matter	Whether stacking is allowed and included

How I would review this coverage

If I were reviewing an auto policy, I would start with the declarations page and find the bodily injury liability limits first.

Then I would find the uninsured and underinsured motorist bodily injury limits.

If the liability limits were much higher than the UM/UIM limits, I would ask what it costs to match them. If UM/UIM was rejected, I would ask how much money was saved and what protection was lost. If I did not carry collision, I would ask whether uninsured motorist property damage is available and what it would actually cover.

Then I would ask about hit-and-run claims, pedestrian or cyclist coverage, passengers, stacking, and claim steps before settlement.

That review may take 15 minutes.

It can prevent a very expensive misunderstanding later.

Final thoughts

Uninsured and underinsured motorist coverage protects you from a risk you cannot control: another driver causing an accident without enough insurance to pay for the harm.

Uninsured motorist coverage may help when the at-fault driver has no insurance or, in some cases, cannot be identified after a hit-and-run. Underinsured motorist coverage may help when the at-fault driver has insurance, but their limits are too low for the full loss.

The most important thing is to know what kind of UM/UIM coverage you actually have.

Check whether your policy includes bodily injury coverage, property damage coverage, or both. Compare the limits with your liability limits. Ask whether it applies to hit-and-run accidents, pedestrians, cyclists, passengers, and multiple vehicles. Check whether your state allows stacking. Ask how the coverage interacts with collision, PIP, MedPay, and health insurance.

Do not reject it just because it sounds optional.

Price it. Read the limit. Understand the trade-off.

Safe driving is important, but it does not control the driver in the next lane. Uninsured and underinsured motorist coverage is there for the day their missing insurance becomes your financial problem.