Updated July 2026
What Is Uninsured and Underinsured Motorist Coverage Insurance?
Uninsured motorist coverage (UM) and underinsured motorist coverage (UIM) protect you when another driver causes a crash but lacks adequate insurance to pay for your injuries or vehicle damage. UM applies when the at-fault driver has zero liability coverage; UIM kicks in when their coverage exists but falls short of your actual costs. Both coverages pay up to your selected policy limits, filling the gap between what the other driver's insurance pays and what you actually owe. Wyoming treats these as optional add-ons, not mandatory coverages, so you must actively choose to include them when building your policy.
- You're stopped at a red light in Cheyenne when another driver rear-ends you at 40 mph. The other driver has no insurance. You suffer whiplash requiring six weeks of physical therapy totaling $8,200, and your vehicle sustains $5,400 in frame damage. Without UM coverage, you pay all $13,600 out of pocket or sue the uninsured driver—who likely has no assets to collect. With UM coverage at $50,000 per person, your policy pays the full $13,600 after you file a claim with your own carrier.
- A driver with Wyoming's minimum liability coverage ($25,000 per person) runs a stop sign and T-bones your car, breaking your collarbone and totaling your vehicle. Your medical bills reach $42,000 and your car's actual cash value was $18,000—$60,000 total. The at-fault driver's liability policy pays its $25,000 limit, leaving you $35,000 short. If you carry UIM coverage at $100,000 per person, your insurer pays the $35,000 gap. Without UIM, you absorb that loss or pursue a lawsuit with uncertain recovery.
- A driver sideswiped your parked truck in a Jackson grocery store lot and fled. You filed a police report within 24 hours documenting the $6,800 in damage and unknown driver. Your UM property damage coverage pays the repair cost minus your deductible, treating the phantom driver as uninsured. Without this coverage, you'd file under your own collision coverage—if you carry it—or pay the full repair yourself.
Who Needs Uninsured and Underinsured Motorist Coverage Insurance?
Carry UM/UIM coverage if you drive frequently in rural areas where emergency response times are long and uninsured driver rates run higher, or if you lack health insurance that would cover crash-related medical bills regardless of fault. It's also critical if you're financing a vehicle—your collision coverage pays for your own car, but UM covers the medical costs that can financially devastate you even after your vehicle is repaired. Drivers who commute daily or carry passengers regularly should prioritize this coverage, as one uninsured driver encounter can erase years of careful budgeting.
Match your UM/UIM limits to your liability limits—if you carry $100,000 per person in liability, carry the same in UM/UIM so you're protected at the same level you're protecting others. If the annual premium is less than 10% of your emergency fund, buy it. If you'd struggle to pay a $30,000 medical bill out of pocket, this coverage is non-negotiable regardless of Wyoming's optional stance.
How Much Does Uninsured and Underinsured Motorist Coverage Insurance Cost?
Adding UM/UIM coverage typically costs $8 to $22 per month, or roughly $96 to $264 annually, depending on your selected limits and whether you include property damage coverage.
- Your chosen UM/UIM limits—matching your liability limits costs more but closes the protection gap most effectively.
- Whether you add UM property damage coverage, which pays for vehicle repairs when the at-fault driver is uninsured.
- Your county's uninsured driver rate—areas with higher percentages of uninsured motorists see slightly elevated premiums.
- Whether you stack UM/UIM limits across multiple vehicles on the same policy, multiplying your available coverage but increasing cost proportionally.
- Your claims history—prior UM claims can raise your rate even though you weren't at fault, as insurers view you as higher-risk for future uninsured-driver encounters.