6.4 Part C Uninsured/Underinsured Motorists

The Problem Part C Solves

Even with mandatory insurance laws, many at-fault drivers cannot pay. The Insurance Research Council (IRC, 2023) estimated about 15% of U.S. drivers are uninsured, and roughly one in three are uninsured or underinsured. Part C — Uninsured Motorists Coverage is first-party protection that steps into the at-fault party's shoes: it pays the insured the bodily injury (BI) damages he would have collected from a responsible driver who lacks adequate insurance.

The critical gate: the other driver must be legally liable. Part C never pays when the insured is the at-fault party.

Uninsured Motorist (UM)

UM pays bodily injury caused by:

• A driver carrying no liability insurance
• A hit-and-run driver (a phantom or unidentified vehicle)
• A driver whose insurer is insolvent

Worked example — $100,000 UM:

Hit-and-Run Rules

Many states require physical contact between the phantom vehicle and the insured before UM applies; others allow a no-contact claim with independent corroboration from a witness. A police report, usually within 24 hours, is generally required.

Underinsured Motorist (UIM)

UIM applies when the at-fault driver has insurance but the limit is less than the insured's damages. Two calculation approaches are heavily tested.

Difference-method, severe injury:

The difference method caps total recovery at the UIM limit; the add-on method can exceed it but never beyond actual damages.

UM vs. UIM

Limits, Stacking, and Settlement Rules

Most states require insurers to offer UM/UIM at limits equal to the liability limits; the applicant must usually reject or reduce it in writing. Limits commonly mirror the liability limits (100/300 liability gives 100/300 UM/UIM).

• Stacking — where allowed, an insured with multiple covered autos can combine per-vehicle UM limits (two cars at $100,000 each gives $200,000). Many policies and states bar this with an anti-stacking clause.
• Consent to settle — the insured must generally get the UM/UIM insurer's consent before settling with the at-fault driver, or risk losing the insurer's subrogation rights and the entire UM/UIM claim.
• Arbitration — many UM/UIM disputes are resolved by binding arbitration rather than litigation.

UMPD and the Collision Overlap

Some states offer Uninsured Motorist Property Damage (UMPD), which repairs the insured's vehicle when an uninsured at-fault driver damages it, usually with a small deductible (around $200 to $250). An insured who carries Collision may instead collect under Part D and let the insurer subrogate, because Collision pays whether or not the at-fault driver is ever identified. UM bodily injury and UMPD are separate elections, and not every state offers the property piece.

Part C Exclusions (Highlights)

UM/UIM does not apply when the insured uses a vehicle without a reasonable belief of permission, when the injury is covered by workers' compensation, or when the insured settles with the at-fault party without consent and impairs the insurer's subrogation.

Notice, Cooperation, and Time Limits

Part C claims are subject to the policy's Part E duties: prompt notice, cooperation, submission to medical exams, and proof of claim. Hit-and-run claims generally require a police report within 24 hours. Failing to report a phantom-vehicle crash quickly is a common reason UM claims are denied, so connect Part C triggers to the Part E procedural duties.

Who Is Covered Under Part C

The insured circle mirrors the rest of the PAP: the named insured and resident family members in any auto, plus other persons occupying the covered auto, and anyone legally entitled to recover because of injury to one of those persons (such as a spouse's loss-of-consortium claim). Unlike Part A, Part C protects the insured's own people rather than third parties.

Reading a UM/UIM Limit

UM/UIM limits use the same split-limit grammar as Part A. A driver with 100/300 liability who accepts matching UM/UIM has $100,000 per person / $300,000 per accident of uninsured-motorist protection. Because the coverage protects the insured's own family — the people most likely to ride in the car — advisors commonly argue UM/UIM limits should be set at least as high as the liability limits. UM/UIM is never a windfall: recovery is always capped at the insured's actual damages, no matter which calculation method or how high the limit.

Why UM/UIM Is Strategically Important

Because about one in three drivers is uninsured or underinsured, UM/UIM converts the other driver's inadequate coverage into the insured's own first-party protection. This is the single most cost-effective way to guard against the large uninsured population on the road.

Exam anchor: UM = no insurance (and hit-and-run); UIM = some insurance, but not enough.