How Is Fault Determined in a Car Accident? Evidence, State Rules and Your Rights

Fault in a car accident is first decided by the insurers, and by a judge or jury if the case goes to court, using the police report, traffic laws, witnesses, photos and vehicle data. Each state then applies its own shared-fault rule, and the deadline to sue is generally two years in California and Texas (Civil Practice and Remedies Code 16.003) and three in Washington.

Who decides who was at fault in a car accident?

Three different people weigh in on fault, and only one has the last word.

• The police officer writes a report with what the officer saw and was told, and sometimes a citation. That report carries weight with adjusters, but it is not a court ruling.
• The adjusters for each insurer decide fault for their own company’s purposes, such as whether to pay your claim and how much.
• A judge or jury decides fault if the case is filed in court. In Texas, the jury or judge sets a percentage of responsibility for each claimant, defendant, settling person and designated responsible third party, stated in whole numbers (Civil Practice and Remedies Code 33.003). Washington’s rule is similar: the jury assigns a percentage to every entity that caused the harm, and the total must equal 100 percent (RCW 4.22.070).

So an adjuster’s decision is the insurer’s position, not the final answer.

What evidence is used to determine fault?

Fault is proved with records and testimony. Adjusters and courts look most at:

1. The crash report. In Texas, an officer who investigates a crash with injury, death or apparent property damage of $1,000 or more must make a written report and file it within 10 days (Transportation Code 550.062). People involved can buy a copy through TxDOT. In Washington, when no officer reports the crash, a driver in a reportable crash must file a written report within four days (RCW 46.52.030).
2. Photos and video. Damage location, final resting positions, skid marks, traffic signals and dashcam or business camera footage often settle what words cannot.
3. Witnesses. A neutral witness who saw the light or the lane change can outweigh both drivers’ accounts.
4. Vehicle data. Federal rules list what a car’s event data recorder must capture if it has one, including vehicle speed, accelerator position and whether the brake was on just before the crash (49 CFR 563.7).

How do traffic laws decide who was negligent?

Every driver owes a basic duty. California’s jury instruction says a person must use reasonable care in driving, keep a lookout for pedestrians, obstacles and other vehicles, and control speed and movement (CACI 700).

Traffic laws make that duty specific. Under the instruction on negligence per se (CACI 418), if a driver broke a safety law and the violation was a substantial factor in causing the harm, the jury must find the driver negligent unless the violation was excused. For a left turn, for example, CACI 704 explains that the turning driver must make sure no oncoming vehicle is close enough to be a hazard (Vehicle Code 21801). The DMV Driver Handbook teaches the three-second rule for following distance, which is why rear-end crashes so often point to the driver behind.

California also sets presumptions for insurance records. A driver whose car was lawfully parked, or who was struck in the rear and not convicted of a moving violation, is presumed not principally at fault for premium purposes (10 CCR 2632.13).

What happens if both drivers were partly at fault?

Shared fault is common, and the state’s rule decides what it costs you.

California’s rule comes from CACI 405: if the defense proves you were negligent and that it was a substantial factor in your harm, your damages are reduced by your percentage of responsibility. Texas bars recovery when your share is greater than 50 percent and otherwise reduces the award by your share (sections 33.001 and 33.012). In Washington, your fault reduces the award proportionately but does not bar recovery (RCW 4.22.005).

Example only. Suppose damages of $50,000 and a finding that you were 20 percent at fault. In all three states the award would be reduced to $40,000. At 55 percent, Texas would allow nothing, while California and Washington would still allow $22,500. Your own facts and the evidence decide the real percentages.

What does the insurance company have to do before it decides fault?

The insurer must investigate before it decides. In California, it must conduct a thorough, fair and objective investigation, and a denial of a third-party claim or a dispute over liability must be in writing (10 CCR 2695.7). That written notice must tell you that the Department of Insurance can review the matter.

Texas lists unfair claim settlement practices, including failing to adopt reasonable standards for prompt investigation and failing to try in good faith to settle once liability is reasonably clear (Insurance Code 542.003). Washington requires an insurer to finish its investigation within 30 calendar days of notice unless that cannot reasonably be done (WAC 284-30-370). It also bars refusing to pay without a reasonable investigation and requires a prompt, reasonable explanation for a denial or a compromise offer (WAC 284-30-330).

How do I dispute a fault decision?

Start by asking the adjuster, in writing, for the basis of the decision and the evidence it relied on. Then answer it with your own: photos, witness names, the crash report and any video. If your own California insurer finds you principally at fault, you may request reconsideration within 30 days of receiving its written notice, and someone other than the original decision maker must review it (10 CCR 2632.13).

If the insurer still will not move, you can file a complaint with the regulator: the California Department of Insurance, the Texas Department of Insurance or the Washington Insurance Commissioner. A complaint can prompt a review, but only a court can make a binding fault finding against the other driver, so watch the filing deadline.

What to do now

1. Get the crash report number and order the report as soon as it is available.
2. Save photos, video and the names and phone numbers of witnesses.
3. Ask whether either car had an event data recorder, and ask that the data be preserved.
4. Keep statements to adjusters short and factual, and do not guess about speed or distance.
5. Ask for any fault decision in writing, with its reasons.
6. Mark your deadline to sue, generally two years in California, per the California Courts, two in Texas and three in Washington (RCW 4.16.080).

Talk to us about a fault dispute

If an adjuster has blamed you for a crash you did not cause, call Beverly Law at (310) 552-6959. We handle car accident cases in California, Texas and Washington. You owe no fees or costs unless we win.

Common questions

Related pages

Car Accident Settlements · Car accident settlements · What to do after a car accident that was not your fault · How do car accident settlements work? · Law Blog

Important: This page is general information, not legal advice, and reading it does not create an attorney-client relationship with Beverly Law. Laws change and every case is different; talk to a lawyer about your own situation. Attorney advertising. Prior results do not guarantee a similar outcome. You owe no fees or costs unless we win. Texas cases are handled by the firm’s Texas-licensed attorneys, Joyce Ondich and John Efstathiou. Last reviewed: 2026-11-12.