Updated July 2026
What Is Uninsured and Underinsured Motorist Coverage Insurance?
Uninsured motorist coverage (UM) and underinsured motorist coverage (UIM) are two parts of the same protection. UM pays when the at-fault driver has zero insurance. UIM pays when the at-fault driver has insurance but their liability limits are too low to cover your medical bills, lost wages, and vehicle damage. Both coverages step in only after you've exhausted the at-fault driver's policy limits, and they cover you, your passengers, and family members in your household.
- You're rear-ended at a stoplight. The other driver admits fault but has no insurance. You have $15,000 in medical bills and $8,000 in vehicle damage. Your uninsured motorist bodily injury coverage pays the $15,000 in medical costs up to your policy limit. Your uninsured motorist property damage coverage pays the $8,000 vehicle repair bill, minus your deductible if your state requires one.
- Another driver runs a red light and T-bones your car. They have Pennsylvania's minimum liability coverage of $15,000 per person. Your medical bills total $40,000. Their liability policy pays the first $15,000. Your underinsured motorist coverage pays the remaining $25,000, up to your UIM policy limit. Without UIM, you would pay that $25,000 out of pocket or negotiate a settlement for less than your actual costs.
- A driver sideswiped your car on the highway and fled the scene. You never identified the driver. Your uninsured motorist coverage treats this as an uninsured driver claim and pays for your injuries and vehicle damage up to your policy limits. You'll need to file a police report within 24 hours and provide it to your insurer to trigger coverage.
Who Needs Uninsured and Underinsured Motorist Coverage Insurance?
You should carry uninsured and underinsured motorist coverage if you drive regularly in Pennsylvania, especially in urban areas where uninsured driver rates are higher. It's critical if you have significant medical expenses that your health insurance won't fully cover, if you're the primary income earner in your household, or if you finance or lease your vehicle and can't afford to replace it out of pocket after an uninsured driver totals it.
Compare the annual cost of UM/UIM coverage to your out-of-pocket maximum on your health insurance plus your vehicle's replacement cost. If an uninsured driver totals your car and injures you, could you cover both without financial hardship? If not, the $100–$200 annual cost of UM/UIM is justified. If you reject it in Pennsylvania, you're betting you'll never be hit by one of the 150,000+ uninsured drivers on the state's roads.
How Much Does Uninsured and Underinsured Motorist Coverage Insurance Cost?
Uninsured and underinsured motorist coverage typically adds $8–$15 per month to your Pennsylvania premium, or $96–$180 per year.
- Your UM/UIM coverage limits — higher limits cost more, but the difference between minimum and double coverage is often only $3–$5 per month.
- Your county's uninsured driver rate — Philadelphia and Allegheny counties have higher uninsured driver rates than rural counties, which can increase premiums slightly.
- Whether you stack coverage — Pennsylvania allows you to stack UM/UIM limits across multiple vehicles on your policy, which doubles or triples your protection but increases cost by 30–50%.
- Your liability coverage limits — carriers often require your UM/UIM limits to match or stay below your liability limits, so raising liability increases UM/UIM cost proportionally.
- Your claims history — a prior UM/UIM claim can increase your rate at renewal, though less than an at-fault collision claim would.