Uninsured and underinsured motorist coverage: the line that answers for the other driver

Uninsured motorist coverage pays when the at-fault driver has no insurance or cannot be identified after a hit-and-run. Underinsured motorist coverage pays when the at-fault driver has insurance but not enough of it. The Insurance Research Council estimated 15.4 percent of U.S. motorists were uninsured in 2023. How the two versions work, the bodily injury and property damage forms, stacking, and the limit worksheet.

Estimates and published averages, not a quote. Not insurance advice. State rules and insurer rules vary. Confirm requirements with your state insurance regulator or a licensed agent in your state.

The gap this coverage exists for

Every other line on your policy assumes the other driver is insured. Liability pays them when you are at fault; collision repairs your car whatever they carry. The scenario neither handles is the one where you did nothing wrong, the other driver caused the crash, and their side of the ledger is empty or nearly empty. Without uninsured motorist coverage, your claim for your own injuries runs against a driver who may have no assets to collect from, and a judgement against an uninsured driver is a document, not a payment. With it, your own insurer steps into the missing policy’s place, up to your limit, and your claim proceeds against a company that can pay. The NAIC puts the coverage among the three major parts of an auto policy, alongside bodily injury liability and property damage liability, which is the correct weight to give it: not an accessory, but the part of the policy that covers the road’s most common broken promise.

Uninsured and underinsured are two different failures

The names are close and the failures are distinct. An uninsured driver has no applicable liability policy at all, or cannot be identified, as in a hit-and-run where the NAIC’s definition expressly includes the driver who leaves. An underinsured driver has a policy, often a legal one, bought at the state minimum, and the failure is arithmetic: their per-person limit is smaller than a serious injury claim, or, in states that compare limits with limits, smaller than your own underinsured limit. The state minimums on this site’s index pages show how low that floor sits in many states, and our state minimum guide works the split-limit arithmetic in full. Your underinsured coverage is therefore not really about the uninsured problem. It is about the minimum-limits problem: the fully legal driver whose $25,000 per-person limit meets your $60,000 injury loss, on a labelled illustration, and leaves a $35,000 gap that only your own underinsured line, your health coverage and your savings are standing behind, provided your underinsured limit is high enough to count under your state’s test, which the next section sets out.

What counts as underinsured: the state test decides

The everyday description of underinsured coverage measures the other driver against your loss. The NAIC consumer guide puts it that way: underinsured motorist coverage pays when an at-fault driver does not have enough insurance to fully pay for your loss. State statutes do not all draw the line there, and the line decides whether the coverage applies at all. Three statutes read for this guide on October 29, 2026 show three different tests.

Texas compares limits with limits. Texas Insurance Code section 1952.103 defines an underinsured motor vehicle as an insured vehicle whose liability limits were originally lower than, or have been reduced by payment of claims from the same accident to, an amount less than the limit of liability stated in the underinsured coverage of the insured’s policy. The comparison is with your own underinsured limit, not with your damages. If the other driver carries $30,000 and your underinsured limit is also $30,000, the other car is not underinsured under that definition, however large your loss.

Washington compares limits with damages. RCW 48.22.030(1) defines an underinsured motor vehicle as one with no applicable liability policy, or one for which the sum of the limits of all applicable liability policies is less than the applicable damages the covered person is legally entitled to recover. Under that wording the same $30,000 policy makes the other car underinsured whenever your legal damages exceed $30,000, whatever your own limit is.

Maryland’s enhanced coverage drops the comparison. Maryland Insurance Article section 19-509.1(a), the version marked in effect when read, defines an underinsured motor vehicle for that coverage as one with liability coverage in an amount less than, more than, or equal to the uninsured motorist coverage on the insured’s policy. Any insured at-fault vehicle qualifies. The practical point for every reader, wherever you live: before you rely on the underinsured line, find out which test your state and your policy form use, because the same crash can fall inside one test and outside another.

Reduced or added on: the payout arithmetic

The second state choice is what happens to your underinsured limit once the at-fault driver’s insurer has paid. Texas Insurance Code section 1952.106 requires underinsured coverage to pay all amounts the insured is legally entitled to recover as damages, not to exceed the policy limit, and reduced by the amount recovered or recoverable from the insurer of the underinsured motor vehicle. The other driver’s payment comes off the top of your limit. Maryland’s enhanced coverage runs the other way: section 19-509.1(h)(2) sets the insurer’s limit at the amount of that coverage without any reduction for the amount paid to the insured that exhausts the applicable liability policies. The other driver’s payment comes first, and your full limit sits on top of it.

Work one labelled illustration on the statute wording, with round figures that are not a quote. The at-fault driver carries a $30,000 per-person limit, the per-person minimum in both Texas and Maryland as listed on this site, and pays it in full. Your underinsured limit is $100,000. If your loss is $60,000, both rules produce the same total: $30,000 from the other insurer and $30,000 from yours, $60,000 in all, because the loss is smaller than either ceiling. If your loss is $150,000, the rules part. Under the Texas reduction, your insurer pays up to $100,000 less the $30,000 recovered, which is $70,000, for a total of $100,000. Under the Maryland enhanced rule, your insurer pays up to its full $100,000 on top of the $30,000, for a total of $130,000. The gap between the two answers, $30,000, is exactly the other driver’s limit.

The third case in the chart is the one drivers miss. With a $30,000 underinsured limit facing a $30,000 at-fault policy and a $60,000 loss, Texas pays nothing under the underinsured line, because the other car is not underinsured by the 1952.103 test, and the total stops at $30,000. Maryland’s enhanced coverage pays its $30,000 on top, for $60,000. In a limits-to-limits state, an underinsured limit set at the state minimum therefore pays nothing against an at-fault driver whose limit equals or exceeds it. Washington’s section 48.22.030, as read for this guide, defines the trigger but does not state whether the payout is reduced by the other driver’s payment; that answer sits in the policy form and the state’s case law, which this guide did not review. Read your own form for the words reduced by, or for a statement that the coverage applies in excess of the other driver’s policy.

Maryland’s enhanced option: the default that takes a written waiver

Maryland shows how much the form you hold can depend on a single signature. Under section 19-509.1(c)(1), in the version marked in effect when read on October 29, 2026, an insurer must provide enhanced underinsured motorist coverage when a private passenger auto policy is bought, unless it is waived. The first named insured may waive it and keep the standard uninsured motorist coverage required by section 19-509, but only by an affirmative written statement, made on a form the Commissioner requires, after written notice of the nature, extent, benefit and cost of the coverage being waived. The form must explain those points in at least 14 point boldface type, and must state that the insurer may not refuse to underwrite a person who declines to waive.

Three further terms in the same section shape the coverage. The enhanced amount must equal the liability coverage on the policy (subsection (f)(2)), which ties this line to your own liability limit by law, the same symmetry the limit worksheet below recommends by choice. A waiver carries forward to renewals and replacement policies unless the first named insured changes it in writing (subsection (c)(3)). And a policy provision requiring binding arbitration of an enhanced underinsured dispute between the insured and the insurer is prohibited and of no legal effect (subsection (k)). The in-effect text applies the waiver regime to new policies issued on or after July 1, 2024, while a renewal policy issued before that date carries the coverage only if the insured elected it (subsection (b)(3)).

One scheduled change belongs with the date. The Maryland statute page also shows a second version of 19-509.1, labelled effective June 30, 2029 per Chapter 514 of 2023, in which the insurer must offer enhanced coverage and the insured may elect it, rather than receiving it by default. Read as of October 29, 2026, that is a scheduled change, not the current rule. A Maryland driver reviewing a policy should look for the enhanced line on the declarations page and for any waiver form in the file, and should expect the default to change on that date unless the law is amended again.

Read the form name before you read the limit

All of this reduces to one habit at renewal. On the declarations page, the underinsured line may be printed as underinsured motorist, as uninsured and underinsured together, or under a state form name such as enhanced underinsured. Ask the insurer, in writing, three things about it. Which test makes a vehicle underinsured under this form: the other driver’s limit against my limit, or against my damages? Is my limit reduced by what the other driver’s insurer pays, or does it apply on top? And is there any written rejection, waiver or election on file for this line? The answers convert the limit printed on the page into the amount actually available in the crash this coverage exists for.

Then rerun the worksheet with the answers. In a state that compares limits and reduces the payout, the useful part of an underinsured limit is the amount by which it exceeds the at-fault driver’s limit, so a limit equal to the state minimum adds little or nothing against a minimum-limits driver. In a state or form that pays on top, every dollar of the limit is available above the other driver’s payment. Neither design is better in the abstract; each prices differently. The point is to buy the line knowing which design you are buying. Not insurance advice: for a policy you hold, the form wording and your state insurance department are the authorities, and a lawyer is the right adviser once a claim is disputed.

The measured size of the exposure

The Insurance Research Council, whose estimates the Insurance Information Institute (III) republishes, estimated that 15.4 percent of U.S. motorists were uninsured in 2023: roughly one driver in seven. The state spread is wide. Triple-I’s republication of the same estimates runs from 5.7 percent of motorists uninsured in Maine to 28.2 percent in Mississippi, which means the value of this coverage line is partly a fact about where you drive, readable on the same state basis as everything else on this site. The underinsured side has no single headline figure in the sources read for this guide, because it depends on the limits drivers around you chose, but the direction is documented: the IRC’s news release of February 17, 2025, on its study Uninsured and Underinsured Motorists: 2017-2023, found one in three drivers (33.4%) was either uninsured or underinsured in 2023. Read together, the two findings describe the actual counterparty pool your policy is written against. The question this coverage asks is not whether the other driver behaved responsibly in general. It is what happens to your bills on the specific day they did not, or could not. Every state’s estimate beside its uninsured motorist rule, and how the IRC builds the ratio, is in uninsured drivers by state.

Bodily injury and property damage are separate forms

Uninsured motorist coverage comes in two forms that are bought, limited and priced separately. Bodily injury form responds to injury losses: medical expenses, lost wages and the other heads of an injury claim, for you and, under the policy’s terms, your passengers and household members. Property damage form responds to your car and, in some states, other property. The two forms do not exist everywhere on the same terms: some states fold property damage into the coverage, some offer it separately with its own deductible, and some do not offer it at all, leaving collision as the route for your car. The NAIC’s consumer guidance answers the totals question directly: if an uninsured driver totals your car, your collision coverage or your uninsured motorist property damage coverage, if you bought it, pays, and either way you will have to pay a deductible. Read your declarations page for which forms you actually hold. A line labelled uninsured motorist with a limit beside it is most often the bodily injury form, and assuming the property form rides with it is the reading error this section exists to prevent.

Required, offered, or rejected in writing: your state’s pattern

States place this coverage in one of three patterns, and the pattern decides how it got onto or off your policy. In some states it is required, and the only decision is the limit. In others the insurer must offer it, and you may reject it or take lower limits, commonly by signing a written rejection or selection form whose exact requirements are set by state law. In the remaining pattern it is simply available to buy. Two practical consequences follow. If your policy lacks the coverage, a signed rejection may be sitting in your file from the day you bought the policy, signed as one form in a stack, and the insurer can produce it. And a rejection signed years ago, at minimum limits, by a driver with no assets to protect, keeps governing a driver whose income and family have changed completely. The review question is not whether a rejection exists. It is whether the reasoning that produced it still describes you. Our state index pages and your state insurance department carry your state’s pattern; the insurer carries your file.

Stacking: when limits add, and when they refuse to

On a policy covering several vehicles, or across several policies in a household, stacking means the uninsured motorist limits for each vehicle or policy add together into a larger available limit for one injured person. Whether that happens is set by state law and policy language together: Pennsylvania presumes stacking unless a named insured signs a statutory waiver, Florida lets insurers offer a non-stacking version, and Minnesota bars adding limits. Ask your insurer in writing for the total limit available to one injured person in one crash. For the statute text, the arithmetic and the court decisions on two policies in one household, read stacked vs unstacked uninsured motorist coverage: the arithmetic and the waiver form. The total available to one person, not the per-vehicle figure printed most prominently, is the number to compare against the injury losses this coverage exists to meet. If the policy is unstacked and the limit is the state minimum, the line is present but thin, which is a decision to revisit rather than a box already ticked.

The limit worksheet: match the line to the exposure

The working default is symmetry: set uninsured and underinsured motorist bodily injury limits at the same level as your own bodily injury liability limits. The reasoning is not tidiness. Your liability limit was chosen, in the how-much worksheet on this site, as the amount of injury loss a serious crash can produce, and that amount does not shrink because the fault sits on the other side of the claim. Work it in three lines. Line one: your current bodily injury liability limit, from your declarations page. Line two: your current uninsured motorist limit, or the word rejected if the line is absent. Line three: the difference, which is the amount of injury loss, in the exact scenario this coverage exists for, that you are currently carrying yourself above line two. If health insurance makes line three feel abstract, narrow the question: health coverage pays medical bills, subject to its own deductibles and networks, and does not pay lost wages or the non-medical heads of an injury claim, which the bodily injury form of this coverage addresses. Price the change at renewal on an identical specification, as with every change this site describes, and get the stacked total in writing while you are at it.

What this coverage does not do

It does not pay when you are at fault and someone else is injured: that is your liability coverage, and no uninsured motorist line substitutes for a thin liability limit. It does not pay your own car’s damage in the states and forms where the property damage version is absent or unbought: collision is that route, with its deductible. It does not replace health insurance, disability insurance or an emergency fund, and an injury claim under it is still a claim, with documentation, negotiation and time attached. It also does not pay instantly: your insurer is entitled to establish that the other driver was uninsured or underinsured and that the loss is covered, which is why the claim file discipline from our claim guide, the police report, the scene record and the other driver’s insurance details taken at the scene, has to be built on the day, not reconstructed later. What the coverage does, when it is present at a matched limit, is narrower and more valuable than any of those warnings: it makes the other driver’s missing or minimum policy a problem your insurer prices, instead of a bill your household absorbs. It does not pay your own medical bills without regard to fault in the way medical payments or personal injury protection does; the difference is set out in medical payments vs PIP.

The claim runs against your own insurer, in the other driver’s shoes

One feature of this coverage surprises drivers at claim time: although the insurer paying is yours, it defends the claim much as the missing insurer would have. Your company is entitled to test fault, to test the size of the loss, and to negotiate, because it has stepped into the at-fault driver’s position rather than acting as your advocate in the negotiation. Two disciplines protect you inside that structure. The first is documentation: the police report, the scene record, the other driver’s details and your medical and wage records are the claim, assembled on the day, under the same record-keeping the III recommends for any claim. The second is consent. Many underinsured motorist forms require your insurer’s written consent before you settle with the at-fault driver or their insurer, because your settlement can extinguish the recovery your insurer is entitled to pursue. Settling the small policy quickly, without that consent, can forfeit the larger claim against your own. Read the consent condition in your policy before any settlement conversation, and if a settlement offer arrives from the other insurer, route it past your own claims department first. In New York, injury claims from uninsured and hit-and-run drivers go through MVAIC, with deadlines in the New York no-fault reference.

Common questions