6.4 Part C Uninsured/Underinsured Motorists

Why Part C Exists

Liability insurance protects the people an insured injures, but it does nothing for the insured when the other driver is the negligent party and carries no insurance or far too little. Part C — Uninsured Motorists (UM) and its companion Underinsured Motorists (UIM) fill that gap by paying the insured for bodily injury the insured is legally entitled to recover from an at-fault uninsured or underinsured driver.

With roughly 15% of U.S. drivers uninsured (Insurance Research Council, 2023), UM/UIM is one of the most practically important coverages in the policy. In many states UM/UIM must be offered with every auto policy and can be rejected only in writing.

Because the at-fault uninsured driver often has no assets to pursue, a liability judgment against them is frequently uncollectible. UM/UIM converts that empty judgment into a real recovery by having the insured's own insurer stand in for the absent or underfunded defendant, up to the UM/UIM limit the insured purchased.

UM vs. UIM

A defining feature: UM/UIM is fault-based. The insured must show the other driver was legally liable and prove the amount of damages — the insured effectively steps into the shoes of a third-party claimant against their own insurer. This contrasts sharply with no-fault Part B Med Pay.

Some states also offer UMPD (Uninsured Motorists Property Damage) for damage to the insured's vehicle by an uninsured driver, but the core national exam focus is bodily injury.

The Difference-in-Limits (Gap) Calculation

Many states use a difference-in-limits or gap approach for UIM: the insured's UIM limit is reduced by the amount actually recovered from the at-fault driver.

Worked Example

The insured suffers proven BI damages of $150,000. The at-fault driver carries only $50,000 in BI liability and pays that full amount. The insured carries $100,000 UIM.

Under the gap approach:

• Insured's UIM limit: $100,000
• Minus amount recovered from at-fault driver: $50,000
• UIM pays: $100,000 − $50,000 = $50,000

Total the insured collects: $50,000 (liability) + $50,000 (UIM) = $100,000. The insured still absorbs the uncovered $50,000 because total proven damages ($150,000) exceed the combined recovery.

Contrast: A few states use an excess/add-on approach where UIM stacks on top of the recovered limit (here paying the full $100,000 UIM on top of the $50,000, for $150,000). Know which model your state follows.

Key Conditions and Exclusions

Part C carries important conditions and exclusions:

1. Consent-to-settle: Settling with the at-fault party without the insurer's written consent and impairing its subrogation rights can forfeit UM/UIM coverage.
2. No duplicate recovery: UM/UIM will not pay damages already recovered from workers compensation, Med Pay, or other UM sources.
3. Owned-but-not-insured exclusion: No UM/UIM while occupying a vehicle the insured owns or regularly uses that is not insured under the policy.
4. Bodily injury only (in most states): Standard Part C covers BI; property damage requires separate UMPD where offered.
5. Insurer insolvency: A liability insurer solvent at issue but later insolvent can turn an otherwise-insured at-fault driver into an uninsured motorist.

Trap: The most-missed condition is consent-to-settle. Settling and signing a release with the negligent driver before notifying your own insurer can wipe out the UIM claim by destroying subrogation.

Who Is Insured and the Hit-and-Run Proof Rule

The Part C insured definition tracks Part A: "you" and family members are covered in any auto and as pedestrians, and other occupants of your covered auto are covered. For a hit-and-run UM claim, most states require the insured to report the accident promptly (often to police within 24 hours) and, in many states, show physical contact between the phantom vehicle and the insured's auto, or supply independent corroborating evidence.

This physical-contact requirement is a frequent exam point: a driver who swerves to avoid a phantom vehicle and crashes without any contact may be denied UM in states that demand actual contact.

Stacking and Limit Selection

In states that permit stacking, an insured with multiple vehicles or policies may add together the UM/UIM limits across covered autos, increasing the total available recovery. The PAP and many state laws limit or prohibit stacking through anti-stacking language, so the availability depends on jurisdiction.

UM/UIM limits are usually offered up to the policy's liability limit and may be selected lower with a signed rejection or reduced-limits form. Because UM/UIM steps in exactly when the insured is hurt by an irresponsible driver, agents are expected to explain the value of matching UM/UIM limits to liability limits rather than buying the bare statutory minimum.

Property-Damage UM and the Phantom-Vehicle Rule

In some states UM coverage extends to property damage (UMPD), paying for damage to the insured auto caused by an uninsured at-fault driver, often subject to a deductible. The exam tests that collision coverage can overlap UMPD, and that an insured generally cannot recover the same damage twice.

The hit-and-run / phantom-vehicle rule is a favorite: to collect UM after an unidentified driver flees, the insured typically must show physical contact with the phantom vehicle (in states requiring it) and report the accident promptly to police and the insurer. A "near-miss" where the insured swerves and crashes with no contact often fails the contact requirement, defeating the UM claim. Recognizing the contact and prompt-reporting conditions resolves most hit-and-run items.