Fault Is Usually a Percentage, Not a Verdict

People expect fault to be binary. In California it usually is not. Understanding that changes how you approach the whole claim.

Pure comparative negligence

California follows a pure comparative fault approach, established by the California Supreme Court in Li v. Yellow Cab Co. in 1975. Responsibility is apportioned by percentage, and a party's recovery is reduced by their own share of fault rather than eliminated by it. Someone found mostly responsible can still recover a reduced amount for their share of the loss.

That is why adjusters talk in percentages, and why "the other guy was at fault" is often the start of a negotiation rather than the end of one.

Who actually decides

In the first instance, the adjusters. Each insurer evaluates its own insured's exposure. When two carriers disagree, they commonly resolve it through inter-company arbitration rather than litigation. Only a small share of collisions reach a court.

An officer's citation or opinion is evidence and influences the outcome. It does not bind an insurer.

What actually moves a fault decision

• Physical evidence. Point of impact, crush direction, debris and skid marks are hard to argue with.
• Independent witnesses. Someone with no stake carries more weight than either driver.
• Video. Dashcam, doorbell, business cameras, transit cameras.
• Traffic law. Right of way, signals, following distance, unsafe lane changes, left-turn duties. A violation that caused the collision is powerful.
• Consistency. An account that stays the same is believed; one that shifts invites scrutiny.

Presumptions that are not rules

Rear-end collisions and left turns across traffic both carry strong practical presumptions, and both can be rebutted — a car that reversed, brake lights that did not work, a vehicle that ran the light. Presumptions are starting points, not conclusions.

If you are assigned a share you disagree with

Ask for the reasoning in writing, ask which specific evidence supports it, and supply what contradicts it. That is a real process with a real path, and it is covered on our page about disputed liability.

Coverage decisions you make now shape how much any of this can cost you later.