California now has one of the highest uninsured motorist rates in the country, according to the latest Insurance Research Council (IRC) study, with an estimated 20.4 percent of drivers on the road without coverage as of 2023. That places the state well above the national average of 15.4 percent and into a tier shared with Mississippi, Tennessee, New Mexico, and Florida.

The IRC, an industry-funded research arm affiliated with the Insurance Information Institute (III), measures the uninsured motorist (UM) rate by comparing UM injury claims to bodily injury claims, a methodology it has used since the 1980s. Its newest report, covering 2017 through 2023, found that the share of uninsured drivers grew nationwide over that window and that California sits near the top of the chart.

What "Uninsured Motorist" Means in California

California requires every driver to carry liability insurance. Effective January 1, 2025, the minimum limits rose to 30/60/15: $30,000 for injury or death to one person, $60,000 per accident, and $15,000 for property damage. Drivers who skip coverage face fines, vehicle impound, and license suspension under Vehicle Code enforcement, but the IRC data shows enforcement gaps remain wide.

UM coverage protects you when the at-fault driver has no insurance. Underinsured motorist (UIM) coverage applies when the at-fault driver carries a policy too small to cover your medical bills and lost income. California Insurance Code Section 11580.2 requires every auto insurer to offer UM and UIM coverage with each policy. Drivers can decline it, but the rejection has to be in writing.

The California Department of Insurance (CDI) confirms that UM bodily injury limits track your liability limits by default. If you carry 100/300 in liability, your UM coverage will be written at 100/300 unless you actively lower it.

Where the Uninsured Concentrate

The IRC does not publish a county-by-county California breakdown, but state and city data point to a clear geography. The Zebra's ranking of the 10 least-insured U.S. cities for auto coverage placed five California metros in the top tier: Los Angeles, Sacramento, San Francisco, San Jose, and Riverside. Historical CDI and Los Angeles Times reporting on California enforcement campaigns has long flagged Los Angeles County, San Bernardino County, Riverside County, and parts of the Central Valley including Fresno as the densest uninsured zones, while Bay Area counties such as San Mateo, Marin, and Santa Clara have historically posted lower UM exposure.

The pattern tracks with income, vehicle age, and commuting distance. Counties with longer median commutes and older vehicle fleets tend to carry higher UM rates because more drivers stretch budgets across rent, fuel, and registration before insurance.

What This Means for Drivers Shopping Coverage

A high local UM rate changes the math on how much UM and UIM you should buy. If roughly one in five drivers around you has no insurance, the odds that your next collision involves an uninsured at-fault driver are meaningful, and your own policy becomes the only meaningful source of recovery.

Three practical takeaways:

  • Do not reject UM coverage. Insurers must offer it, and the default UM limit equals your liability limit. Signing the rejection form leaves you exposed.
  • Consider buying UM/UIM above the new 30/60 floor. Hospital bills for a single ER visit after a moderate crash can exceed $30,000, and the IRC has documented that roughly one in three drivers nationally is either uninsured or underinsured.
  • Shopping protects you under Prop 103. California Proposition 103 prohibits insurers from raising your rate solely because you file a UM claim after a no-fault accident. Comparing carriers on UM and UIM limits, not just liability, is the lever drivers in high-UM counties have.

For drivers in Los Angeles, San Bernardino, Riverside, and Fresno counties, the IRC data is a signal to price out higher UM/UIM limits, not to settle for the 30/60/15 statutory floor.