The Number That Should Change How You Buy Insurance
According to the Insurance Research Council, roughly 17% of California drivers on the road carry no auto insurance at all. In parts of Los Angeles and the Central Valley the local rate exceeds 25%. In practical terms: on any given commute, one in every six cars around you is uninsured.
That statistic is why California law requires every auto policy sold in the state to include an offer of Uninsured/Underinsured Motorist (UM/UIM) coverage in writing. If you rejected it, the rejection had to be signed. Most drivers who don't have UM don't remember rejecting it — they were quoted a minimum-limits policy and clicked through without realizing what they were opting out of.
What Uninsured Motorist Coverage Actually Does
UM/UIM pays for your injuries, your passengers' injuries, and in some cases your vehicle damage when the at-fault driver has no insurance or not enough insurance to cover the harm they caused.
There are two flavors. Uninsured Motorist Bodily Injury (UMBI) pays for medical bills, lost wages, and pain and suffering when a hit-and-run driver or truly uninsured driver injures you. Underinsured Motorist (UIM) fills the gap when the other driver has coverage but their limits are exhausted — for example, they carry the new California minimum of $30,000 per person, but your medical bills are $80,000.
Why It's So Cheap
UM/UIM is one of the cheapest coverages on a California auto policy. Adding 100/300 UM/UIM to a standard policy typically costs $8–$20 per month — usually less than the tax on your monthly cell phone bill.
The reason it's cheap is that it's structured as first-party coverage on your own policy. Your carrier pays your claim first, then may subrogate against the at-fault driver. There's no third-party litigation cost baked into the price the way there is for standard liability.
What Happens Without It
If you're hit by an uninsured driver and you have no UM coverage, your options are limited and painful. You can sue the at-fault driver personally, but if they had no insurance they usually have no assets — you'll spend legal fees pursuing a judgment you can't collect on.
Your own collision coverage will pay to repair your car (minus your deductible), but collision does not pay for your medical bills, your lost wages, or your pain and suffering. Your health insurance may pay some medical bills, but they will often demand reimbursement from any settlement you eventually receive.
Hit and Run — This Is Where UM Really Earns Its Keep
A hit-and-run crash in California is treated as an uninsured motorist event for UM purposes even if the at-fault driver is never identified. As long as you report the crash to police within a specified window (24 hours in most policies) and to your carrier within 30 days, your UM coverage applies as if the fleeing driver had zero insurance.
Without UM, a hit-and-run leaves you with medical bills and lost income and no meaningful recovery path. This alone is a good enough reason for every California driver to carry UM.
How Much UM Should You Carry?
Match your UM/UIM limits to your liability limits. If you carry 100/300 in bodily injury liability, carry 100/300 in UM/UIM. The logic: you've decided that 100/300 is the amount of harm you want protection for. It shouldn't matter whether that harm is caused by you (liability) or done to you (UM).
The one exception is if you already carry a personal umbrella policy that includes UM/UIM excess coverage. In that case, you can often carry standard 100/300 or 250/500 underlying UM and let the umbrella extend it to $1 million.
The Bottom Line
Uninsured motorist coverage is the highest-leverage line on a California auto policy: it's cheap, it protects you from the choices of thousands of drivers you can't control, and it's the only coverage that pays you for hit-and-runs. If you don't currently carry it, ask for a quote to add it — the number is almost always small enough to make the decision obvious.