If the driver who hit you in California had no insurance, or carried a policy too small to cover what you lost, your own uninsured and underinsured motorist coverage (UM/UIM) is usually what pays. California writes specific rules for that coverage into the Insurance Code, and a few of them surprise people at the worst possible time. Here is what actually governs a UM/UIM claim in this state.
What your insurer has to offer
Every California auto liability policy has to include uninsured motorist bodily injury coverage equal to your liability limits, unless you sign a written waiver cutting it down or removing it. That mandate is in Insurance Code section 11580.2(a).1 The rejection has to be in writing, and once you sign it, it stays in effect until you change it, so plenty of drivers who "declined" UM years ago have no memory of doing it.1
If you keep the coverage, the statutory floor is $30,000 for injury to one person and $60,000 per accident under section 11580.2(m).1 Those figures track California's minimum liability limits, which rose to 30/60/15 on January 1, 2025 under SB 1107, the Protect California Drivers Act, the first increase in more than half a century.23 They climb again to 50/100/25 on January 1, 2035.3 You can carry UM limits all the way up to your liability limits, and for a serious injury the statutory minimum rarely stretches far.
Underinsured coverage fills a gap, it doesn't top up your losses
This is the rule that trips up the most people. In California, "underinsured" does not mean the at-fault driver simply didn't carry enough for your injuries. Under section 11580.2(p), a vehicle counts as underinsured only when its bodily injury limits are lower than your own UM/UIM limits.1 If the two are equal, or if yours are lower, you have no UIM claim at all, however badly you were hurt.
UIM also pays only the gap. You first have to exhaust the at-fault driver's liability limits through a settlement or judgment and give your insurer proof of that payment.1 Your UIM carrier then credits what you already collected against your limits and pays the remainder.1 Say your UIM limit is $100,000 and the driver who hit you carried the $30,000 minimum. Your ceiling is the $70,000 difference, not $100,000 layered on top of the $30,000. If your damages come to $60,000, the $30,000 you already recovered leaves $30,000 for the UIM carrier.
Hit-and-run and phantom vehicles
UM coverage reaches hit-and-run drivers, but California attaches a hard condition. For a bodily injury claim involving an unidentified vehicle, section 11580.2(b) requires actual physical contact between that vehicle (or a car it struck) and you.1 A driver who forces you off the road without touching anything is a "phantom" vehicle, and with no contact there is no UM bodily injury claim under the statute. You also have to report the accident to police within 24 hours and file a sworn statement with your insurer within 30 days.1 Start the police report right away. California crash reports come from the CHP,4 and thatcarhitme.com covers how to pull one for California.
Damage to your car is separate, and optional
The coverage in section 11580.2 handles bodily injury, not your vehicle. California puts property damage in its own statute, section 11580.26, and it works differently.5 Uninsured motorist property damage (UMPD) pays for collision damage to your car from an uninsured driver, capped at the vehicle's actual cash value or $3,500, whichever is less.5 It's optional, and a named insured can decline it under section 11580.26(c).5 Unlike a bodily injury claim, UMPD requires the uninsured vehicle or its driver to be identified, by license plate or otherwise, in addition to actual physical contact, so a genuinely unknown hit-and-run driver won't trigger it.5 You have to report the accident within 10 business days.5 Because $3,500 rarely covers a real repair or a car's lost market value, drivers who want their vehicle fully protected lean on collision coverage, plus a diminished value claim against the at-fault side when one exists.
The two-year deadline that isn't the one you think
Every California injury claim runs against a two-year statute of limitations measured from the crash date under Code of Civil Procedure section 335.1.6 A UM/UIM claim carries its own, stricter version. Under section 11580.2(i), reporting the claim to your insurer does not preserve it. Within two years of the accident you have to do one of three things: file suit against the uninsured motorist, agree with your insurer on what's owed, or formally begin arbitration by sending written notice by certified mail.1 Miss all three and the claim can be barred even though you opened it on day one. Your insurer does have to warn you in writing at least 30 days before that deadline expires.1 Once arbitration is under way, section 11580.2(i)(2) generally allows five years to finish it.1 Vehicle damage has a longer three-year clock under Code of Civil Procedure section 338(c)(1), but it's the UM deadlines that quietly close claims.7
Fault still reduces what you collect
A UM/UIM claim is against your own insurer, yet it stands in the shoes of the driver who hit you, so you still have to prove that driver was at fault. California's pure comparative negligence rule then applies. Under Li v. Yellow Cab Co., a jury or a UM arbitrator assigns each side a share of fault and cuts your recovery by your percentage, even when you carry most of the blame.8 California is an at-fault state with no no-fault PIP requirement, so nothing automatically pays your medical bills while this sorts out, which is a large part of why UM/UIM and optional MedPay matter here.9
If your crash involved a driver with no coverage or thin limits, pull your own declarations page and read the UM/UIM line before you speak to anyone, and watch the two-year arbitration deadline closely. When the numbers are serious or the insurer stalls, you can find an attorney who handles California UM/UIM claims.
This is general information about California law, not legal advice.
Sources
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California Legislative Information, Cal. Ins. Code § 11580.2. https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?sectionNum=11580.2&lawCode=INS
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California Legislative Information, SB 1107 (2021-2022), Protect California Drivers Act. https://leginfo.legislature.ca.gov/faces/billNavClient.xhtml?bill_id=202120220SB1107
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California Legislative Information, Cal. Veh. Code § 16056. https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=VEH§ionNum=16056.
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California Highway Patrol, Collision Report (CHP 190). https://www.chp.ca.gov/notify-chp/collision-report-chp-190/
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California Legislative Information, Cal. Ins. Code § 11580.26. https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=INS§ionNum=11580.26
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California Legislative Information, Cal. Code Civ. Proc. § 335.1. https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?sectionNum=335.1&lawCode=CCP
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California Legislative Information, Cal. Code Civ. Proc. § 338(c)(1). https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?sectionNum=338.&lawCode=CCP
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Li v. Yellow Cab Co. (1975) 13 Cal.3d 804, CourtListener. https://www.courtlistener.com/opinion/1139343/li-v-yellow-cab-co/
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California DMV, Insurance Requirements for Vehicle Registration. https://www.dmv.ca.gov/portal/vehicle-registration/insurance-requirements/