The most common reason people never call a lawyer after getting hurt is that they think they blew it. They were going a little fast. They stepped off the curb before the signal changed. They walked past the wet floor sign without reading it. Under California law, none of that automatically ends a claim, and any San Mateo personal injury attorney who handles collision and premises cases sees viable claims abandoned every year over this misunderstanding. California uses pure comparative fault, which is the most forgiving version of the rule in the country.
What changed in 1975 and why it still matters
Before the California Supreme Court decided Li v. Yellow Cab Co. in 1975, the state followed contributory negligence. If an injured person contributed to their own harm at all, even slightly, they recovered nothing. Li replaced that with comparative negligence, and the court chose the pure form rather than the modified version most states adopted.
The difference is significant. In a modified comparative fault state, a plaintiff found 51 percent responsible walks away empty. In California there is no cutoff. A jury can find you 80 percent at fault and you still recover 20 percent of your proven damages. Someone with $200,000 in medical bills and lost income who bears most of the blame is looking at a reduced recovery, not a dismissed case.
How fault percentages actually get assigned
Nobody hands out percentages by formula. A jury allocates them after hearing evidence about what each party did and how much that conduct contributed to the harm. Before trial, the numbers come from negotiation, which means the insurance adjuster’s opening figure is an argument rather than a finding.
That opening figure tends to be generous to the insurer. An adjuster reviewing a rear-end collision on El Camino Real might assign the injured driver 25 percent for a claimed sudden stop, cutting a $60,000 evaluation to $45,000 before the conversation about medical bills even starts. The percentage is negotiable in both directions, and it usually moves once someone pushes back with documentation instead of recollection.
The evidence that moves the number
Fault allocation shifts on records, not on how confidently either side describes the accident:
- Event data recorder downloads showing speed, throttle, and brake application in the seconds before impact
- Cell phone billing and usage records establishing whether either driver was distracted
- Surveillance footage from nearby businesses, which is often overwritten within two to four weeks
- Maintenance and inspection logs in premises cases, which reveal how long a hazard existed before anyone was hurt
- Statements from independent witnesses, gathered while their memory is intact and their contact information is current
Recorded statements work the other way. An adjuster asking whether you saw the other car “at the last second” is building a comparative fault argument, and there is no obligation to give a recorded statement to the opposing insurer.
Comparative fault beyond car accidents
The rule follows the injured person into almost every negligence claim. A shopper who slips in a grocery aisle can be assigned fault for wearing worn-out shoes or looking at a phone, while the store answers for how long the spill sat unaddressed. Nonuse of a seatbelt is admissible in California as comparative fault, though the defense has to prove the injuries would have been meaningfully less severe with one. Lane splitting, by contrast, is legal here, so a motorcyclist cannot be assigned fault simply for doing it.
Dog bite claims work differently again, since California imposes strict liability on owners. Comparative fault can still reduce recovery if the injured person provoked the animal or ignored clear warnings.
Two statutes that can matter more than your percentage
Proposition 51, codified at Civil Code section 1431.2, splits how multiple defendants pay. Economic damages like medical expenses and lost wages remain jointly and severally owed, so any liable defendant can be pursued for the full amount. Noneconomic damages, meaning pain and suffering, are divided according to each defendant’s share of fault. In a multi-vehicle crash on the Peninsula, that allocation often determines whether a case is worth pursuing against a lightly insured driver.
Proposition 213, at Civil Code section 3333.4, is the harsher one. A driver who was uninsured at the time of the crash cannot recover noneconomic damages at all, even when the other driver caused the collision entirely. The same bar applies to someone convicted of DUI arising from the incident. Economic losses stay recoverable, but the pain and suffering component disappears, which changes case value dramatically.
Timing sits underneath all of it. Most California personal injury claims carry a two-year statute of limitations, and claims against public entities like Caltrans, SamTrans, or a city require a written claim within six months. Waiting to see whether your share of fault is disqualifying is how a recoverable case becomes an expired one.
Partial responsibility reduces what you collect and nothing more, and the percentage an adjuster proposes in the first phone call is rarely the percentage a case is worth. If you have been told you were at fault, or you assume you were, have the allocation reviewed by a San Mateo personal injury attorney before you accept a number or let a deadline pass. The evidence that lowers your share tends to disappear well before the filing window does.
