Fault Determination Rules in California Car Accidents

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Jeffrey Johnson is a legal writer with a focus on personal injury. He has worked on personal injury and sovereign immunity litigation in addition to experience in family, estate, and criminal law. He earned a J.D. from the University of Baltimore and has worked in legal offices and non-profits in Maryland, Texas, and North Carolina. He has also earned an MFA in screenwriting from Chapman Univer...

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UPDATED: Jul 16, 2021

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The least you need to know…

  • California is a fault-based state for determining responsibility for car accidents.
  • The pure comparative negligence standard means that fault can be shared in all circumstances.
  • California also has a rule that means if you are breaking the law in some way when the accident happens, you will be presumptively at fault.

The fault determination rules in California car accidents are not quite like any other state’s. California auto insurance claims laws are fault-based, like in most other states, but fault can be determined in two different ways:

Not only will fault be determined based on which party is most responsible (i.e. negligence), but if one of the vehicles is in violation of California law at the time of the accident, that vehicle’s driver will be found to be at fault.

In this article, we’ll explain the ins and outs of how fault works in California and answer some frequently asked questions on Fault determination. If you need to consult with a car accident attorney to answer more specific questions, you can start your search by putting your ZIP code into our search tool above.

How do you determine who is at fault in an accident in California?

There are two primary methods of determining fault for auto accidents in California. The first and oldest method is the common law theory of negligence. To show that the other driver is at fault using the common law theory of negligence, the injured party must show that the other driver didn’t operate the vehicle with enough care, often using police reports, witness statements, and investigatory tools. The injured party must prove that the negligent actions of the other driver were the cause of the damage and injuries.

The second main way that California accident fault is determined is by statute. If the driver of a car involved in a car accident violated the California Vehicle Code, then the driver will often be presumed negligent, which is called negligence “per se.”

Determining Who Was at Fault by Proving Negligence

Determining fault by proving negligence in accidents in California began as a “common law” tort theory, meaning that over time the courts created the theory to find a way for an injured party to receive compensation from the party at fault. In modern times, the legislatures of California and other states have altered the theory of negligence by creating laws that change the way negligence is evaluated and proven. 

To show that the other party was at fault for a California accident, the injured party must generally show that the other driver didn’t operate their vehicle with an appropriate level of care. The standard by which drivers are judged is called the “reasonable person” standard. Every driver on the road has a duty to operate their vehicle with ordinary care, or in other words, every driver has a duty to use a reasonable amount of caution when operating their vehicle.

Injured parties in auto accidents in California must also show that the other driver “breached” their duty to drive with caution, or that they didn’t use the level of caution or care required. The injured party must then prove that the negligence of the other driver was the cause of the accident and that there was damage or injury that resulted from the negligence.

If the injured driver proves that the other driver didn’t use the required amount of care in operating the vehicle and was therefore negligent and that the negligence was the cause of the injuries, the injured driver will be entitled to compensation in the amount of their damages as a matter of law. 

Determining Who Was at Fault by Showing Violation of a Statute

Another common way to determine fault is to determine whether either party violated California laws. If a driver violates a provision in the California Vehicle Code, for example, which then results in an accident, that driver can be considered “negligent per se,” which means that he or she is presumed to be negligent or, again, is presumed to have failed to exercise enough care and caution in the operation of his or her vehicle. 

Negligence per se, like regular negligence, was originally a “common law” doctrine, meaning that judges designed it as a way to assign fault in accidents. In California, the negligence per se doctrine was adopted as a statute by the legislature and is represented in the California Evidence Code under Section 669. Basically, Section 669 just requires that the statute violated was designed to prevent accidents of the type that occurred.

It’s fairly easy to show that a driver was negligent in a car accident when the driver violated the California Vehicle Code, as most of the statutes in the Vehicle Code were designed to prevent car accidents and protect other drivers. If a driver involved in an accident is presumed to be negligent, they essentially have to prove they weren’t negligent or they will be held responsible for the accident.

Often, the police report from the accident will state whether there is negligence on the part of a driver under the statute.

Comparative Negligence and Fault in California Accidents

An auto accident doesn’t necessarily end when one party shows the other party was negligent. In California, as in many other states, the amount that a negligent party may be required to pay to the injured party can be reduced if the injured party contributed to the accident by acting negligently themselves. 

Find out more about how different states determine fault in car accidents.

California operates under a pure comparative negligence theory of liability, which theoretically allows a party to collect money for their injuries even if they were 90% at fault for the accident. Pure comparative negligence works in California accidents by providing for the assignment of a certain percentage of fault to each party, then reducing the damages by that percentage.

For example, if an injured party suffered $100,000 in hospital bills and pain and suffering, and was determined to be 90% at fault, the damage award would be reduced by 90% from $100,000 to $10,000.

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Frequently Asked Questions: Fault Determination in California

Now that we’ve covered the basics, let’s get into some frequently asked questions about fault determinations in California car accidents.

Is California a no-fault state for car accidents or a fault-based state?

California is a fault-based state and uses pure comparative negligence to determine who is responsible for the accident.

Who determines fault in an auto accident in California?

Fault is determined by different parties depending on when the determination is reached. The insurance companies involved will reach a conclusion of fault based on evidence gathered. Often they will work with the police and the drivers involved.

If one party thinks the finding is wrong, they can challenge it through a lawsuit. This may be barred by the insurance policies, but if the accident goes through a trial, a judge or jury will ultimately decide who was at fault.

Investigators have experience with car accidents, sometimes determining fault by location of the damage that resulted. For example, in a t-bone accident, fault in California and most other states will lie with the car that was damaged in the front. 

Determining fault in a car accident with a left turn would depend less on the physical evidence than on witness testimony or other evidence. Normally a car making a left turn should yield, but speed, intoxication, and lights can all alter this conclusion. 

Remember though, that fault can be shared in California, and that violation of the law will make a driver negligent per se. In a u-turn accident, fault in California would be easy to determine if the u-turn was illegal. If it was permitted, though, a more thorough investigation would be required.

Lying in order to get a more favorable determination is likely insurance fraud. According to the Insurance Information Institute, fraud accounted for more than fifteen percent of all claims paid out in 2012.

How long does an insurance company have to determine fault?

California law gives insurance companies 40 days to investigate a claim. If the company needs more time, it must notify you every 30 days. Once a determination is reached and agreed to, payment must be issued within 30 days as well.

What are the consequences of a car accident in California?

An at-fault accident in California adds points to your license if

If you’re not at fault, the other driver’s liability insurance should cover all of your damages and injuries. For example, if your car is a total loss, you’re not at fault, California insurance minimums should cover replacing your car. Serious injuries or multiple vehicle accidents may exceed the driver’s liability coverage, however.

In that circumstance, you may need to pursue litigation.

Wrapping it Up

If you were in a car accident, particularly if injuries were involved, be sure to contact a California attorney to help you sort through who was at fault and what, if any, compensation you can expect to recover.

Your lawyer will discuss the details of the accident with you, carefully read police reports, negotiate with other attorneys or insurance adjusters on your behalf, and may hire an accident reconstructionist or an investigator if those resources are necessary.

Did we answer all your questions? If you have more specific questions, you might need to reach out to a car accident lawyer.

You can find an experienced car accident attorney near you by entering your ZIP code into our search tool.


  1. https://leginfo.legislature.ca.gov/faces/codesTOCSelected.xhtml?tocCode=VEH&tocTitle=+Vehicle+Code+-+VEH
  2. https://www.search-california-law.com/research/ca/EVID/669./Cal-Evid-Code-Section-669/text.html
  3. https://www.iii.org/article/background-on-insurance-fraud

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