Fault and Liability
How California law actually decides who's responsible after a Santa Clarita accident
When you were there, fault can feel obvious. The other driver ran the light, followed too closely, or drifted into your lane. It is natural to assume everyone will see it the same way.
They often do not. The other driver, that driver's insurance company, and even witnesses may see the same collision differently, which is why fault is something to examine rather than assume.
This guide follows a dispute over fault in the order it usually unfolds: competing stories, the evidence that breaks the tie, the way responsibility gets divided, and what to do when the insurance company disagrees with you.
Jump to the stage you're in:
Key Takeaways
- Do not assume the other person will admit fault. Drivers often remember the same collision very differently.
- Fault is determined by evidence. Witness accounts, police reports, photographs, vehicle damage, video, and traffic controls all feed into the decision.
- A police report can be important without being conclusive. It is not the final word on civil liability.
- Independent witnesses can become the tiebreaker when the drivers tell conflicting stories.
- California uses comparative fault. Responsibility can be shared, and recovery is generally reduced by the injured person's percentage rather than eliminated.
- An insurance adjuster's percentage is not a court judgment. It is a claim position that can be questioned.
- Preserve evidence early. Witnesses forget, vehicles get repaired, and video gets overwritten.
- If the insurance company disagrees with you, ask why. Knowing the facts it relies on shows you what needs to be addressed.
Fault Is Not Always Obvious
Two people can stand at the same intersection and describe the collision in completely different ways. Stories can also change once the adrenaline wears off, once insurance gets involved, or once someone realizes what an admission could cost.
That is why claims professionals warn against relaxing about liability too early, even when the police report looks favorable. Until the insurance company has actually accepted responsibility, fault is still an open question.
For a broader look at where fault fits in the overall claim, see the Navigating the Claim overview. The first hours matter too, and the Immediate Steps guide covers what to do while the facts are still fresh.
How an Insurance Adjuster Looks at Fault
An adjuster typically builds a picture of the accident from several sources:
- A conversation with the insured driver
- The police report
- Photographs and vehicle damage
- Witness interviews
- The injured person's own account, sometimes through a recorded statement
A recorded statement becomes part of the claim file, so it is worth being careful with. Our guide to dealing with insurance companies explains what to expect from that first call.
Adjusters do not simply accept their own insured's version of events. A statement that conflicts with the photographs, the vehicle damage, or a witness gets questioned internally, which is one reason consistent, well-documented evidence on your side matters.
When Both Drivers Say the Other One Was at Fault
This is the classic dispute: two drivers, two versions, and no video. In that situation the adjuster looks for something outside the two competing accounts to act as a tiebreaker.
That may be an independent witness, the officer's findings, physical evidence, or simply which account is more consistent and credible. The next sections cover each of these in turn, starting with the one people tend to overweight.
The Police Report Can Be Important Without Being the Final Word
A police report is often strong evidence, particularly when it records independent witness statements and the officer's own observations. It does not, however, decide civil fault.
The officer may not have seen the collision, may have relied on incomplete statements, or may have recorded something incorrectly. For that reason, read the report closely, especially the statements attributed to each person.
If you find a mistakeWhat to do about an error in the report
Identify exactly what is wrong. Depending on the circumstances, it may be appropriate to provide additional information to the investigating agency or to request a supplemental report.
The aim is to address significant factual inaccuracies promptly. An uncorrected error can be raised against you later, and it is harder to deal with after memories and evidence have faded.
Independent Witnesses Can Break the Tie
When the drivers disagree, someone with no relationship to either side and no financial stake in the outcome can carry particular weight.
A witness does not need to have seen the impact itself. Someone who noticed a car speeding, a driver looking down at a phone, or something said right after the crash can still matter.
How much weight a witness gets depends on:
- Where the person was standing
- What the person could actually see
- Whether the account stays consistent over time
- Whether it fits the physical evidence
At the sceneGet witness information early
If you are able, get each witness's name and contact information, ask whether they would be willing to be contacted later, and encourage them to stay and speak with the officer.
Cooperation and memory both fade quickly. The goal is to preserve what the witness actually observed, not to shape what the witness says.
Physical Evidence Can Tell a Different Story
People have memories, opinions, and motives. Vehicles and roadways do not. The location and severity of damage can show the direction and force of an impact, and in larger cases an accident reconstruction expert may analyze it.
Damage can also be deceptive. A vehicle may look only lightly damaged from the outside while having structural or frame damage underneath.
What the evidence can showCategories of physical evidence
- Vehicle and frame damage
- Debris, which can point to the area of impact
- Skid and tire marks, which can show braking
- Final resting positions of the vehicles
- Roadway layout, which shows what each driver could see
- Traffic signals and signs
- Lighting conditions
- Photographs and video
Minor Vehicle Damage Can Create a Different Problem
An insurer or defense attorney may argue that a collision with little visible damage could not have caused the injuries claimed. That argument is not necessarily correct. Exterior damage does not reveal what happened inside the vehicle or whether hidden structural damage exists.
It is one more reason to photograph and document the vehicles before repairs change them. The Evidence & Documentation page explains what is worth keeping.
Video and Photographs: Evidence That Disappears
Video can settle a dispute in seconds. It can also vanish. Many surveillance systems automatically overwrite older footage, so identifying likely sources early matters.
Think about where a camera might have been pointed:
- Businesses and parking lots near the crash
- Homes with doorbell or security cameras
- Dashcams, including your own and other drivers'
- Phones belonging to you, passengers, or bystanders
Video does not necessarily wait for a lawsuit. By the time anyone realizes how important a recording would have been, the system that captured it may have recorded over it weeks earlier.
Nearby home and business cameras are a common source of video, and many overwrite footage automatically.
Photographs are some of the easiest evidence to preserve. Photograph the vehicles, the scene, road conditions, traffic controls, and property damage before they change. Injuries change too, so photographing them over time can help.
The rule is simple: document what can be documented while it exists.
Comparative Fault: Sometimes Responsibility Is Shared
California generally does not treat personal injury cases as all-or-nothing. Under the pure comparative-fault rule recognized in Li v. Yellow Cab Co., an injured person whose own negligence contributed to the harm can still recover, but the recovery is reduced by that person's share of responsibility.
The defense also has a burden. As reflected in the jury instruction CACI No. 405, the defendant must prove that the injured person was negligent and that the negligence was a substantial factor in causing the harm. Some comparative-fault arguments are weak, and others may be persuasive.
ExampleHow shared fault plays out in practice
Suppose a driver is accused of speeding at the moment another driver turned across the lane in front of them. The turning driver may argue the speeding contributed to the crash. Whether that is persuasive depends on the evidence, and the defense must connect the speed to the harm that occurred.
If responsibility is divided, the recovery is generally reduced by the injured person's percentage rather than eliminated. The Case Value page covers how this fits into the bigger valuation picture.
More Than One Person Can Be Responsible
Several parties can contribute to a single injury: more than one driver, a trucking company and its driver, or a property owner and a maintenance contractor.
California comparative-fault rules allow responsibility to be apportioned among multiple responsible parties in appropriate cases, and non-economic damages are treated differently when more than one defendant is involved (see Civil Code section 1431.2). Multi-party situations are common in truck accidents, and they can also arise in slip and fall claims. Everyday collisions are covered in the car accident guide.
Unfamiliar terms such as "apportioned" or "substantial factor" are explained in the Glossary.
What Happens When the Insurance Company Disagrees?
When an insurer disputes liability, a useful first move is to ask what facts it is relying on and what information it feels it is missing.
The gap is often fixable. It may be a medical record the adjuster has not seen, photographs that never reached the file, an error in the police report, or a witness statement nobody collected.
Repeating the same argument rarely changes the outcome. New documentation that speaks to the adjuster's specific concern sometimes does.
Questions worth asking:
- What facts or evidence support the fault percentage you have assigned?
- What information is missing from the file?
- Has a witness been contacted, and what did the witness say?
- Does the position depend on the police report, and if so, is that report accurate?
If an offer arrives that reflects a fault reduction, see Settlement Offers before responding.
What If You Are the One Being Sued?
Most of this page speaks to someone who was hurt. Fault disputes cut both ways, though, and a driver who believes the other driver caused the accident can still be sued. This section is general information, not advice about a lawsuit you are facing. This site is written for injured people and does not provide representation to defendants.
It starts with papers delivered to you. A lawsuit begins when a complaint is filed in court and a summons and complaint are served on the defendant. The summons generally directs you to file a written response with the court within 30 days (Code Civ. Proc., § 412.20).
Do not ignore it. If no response is filed in time, the plaintiff can ask the court to enter a default, and the court can then decide the case without hearing from you (Code Civ. Proc., § 585). A default can sometimes be set aside, but that is a harder process, and you should not count on it.
Tell your insurance company right away. Your liability policy may include a duty to defend, which means the insurer may provide and pay for a lawyer to defend the lawsuit. Policies ask for prompt notice, and delay can lead to coverage disputes. Send the papers to your insurer as soon as you receive them and keep copies of everything.
An insurer sometimes agrees to defend while issuing a reservation of rights. That is a notice that it is handling the lawsuit but may later dispute whether the policy actually covers the claim. It does not mean the insurer has denied coverage, and it does not mean you should stop cooperating, but it is a sign that coverage is not settled. The Glossary defines the term.
Insurance may not cover everything. If the claim could exceed your policy limits, or the insurer has reserved its rights, many people consult a lawyer of their own. If you have no insurance, or your insurer denies coverage, speak with a California attorney promptly, because the response deadline keeps running.
If you were hurt too. Both drivers are sometimes injured, and each blames the other. A related claim you have against the person suing you generally has to be raised in the same lawsuit, through a cross-complaint, or you may lose the right to bring it later (Code Civ. Proc., § 426.30). Tell your lawyer about your injuries at the start. Separate deadlines also apply to your own claim. See California Filing Deadlines.
What happens next. After a response is filed, the case follows the stages described in How Personal Injury Cases Work, including discovery and settlement discussions, and most are resolved without a trial. Avoid discussing the case with the other side or on social media while it is pending, since statements can be used in the lawsuit.
Do Not Guess About What You Do Not Know
Accuracy matters more than filling gaps. Estimates of vehicle speed or the color of a signal can later be challenged, and a guess that turns out to be wrong can damage your credibility on points you actually know well.
It is better to say that you do not know or do not remember than to present an assumption as a fact.
The Real Question Is Not Simply "Who Was at Fault?"
A careful investigation breaks the single question into several smaller ones:
- What actually happened?
- What could each person reasonably have seen or done?
- Did that conduct cause the accident and the claimed injuries?
- What do the physical evidence and witnesses show?
- Should other parties be examined?
Frequently Asked Questions
If the other driver caused the accident, why doesn't the insurance company automatically accept responsibility?
Because the insurance company conducts its own investigation. The other driver may provide a different account, witnesses may tell a different story, or the insurer may identify evidence suggesting that its insured was not entirely responsible. An insurance company's position can be disputed and is not automatically the final legal determination.
If the police report says the other driver was at fault, does that settle the issue?
No. A police report can be persuasive and important, but it is not necessarily conclusive in a civil personal injury case. The officer may not have witnessed the collision and may have relied on information that later proves incomplete or inaccurate.
What if both drivers say the other one caused the accident?
The investigation generally turns toward the available evidence. Independent witnesses, photographs, video, vehicle damage, debris, skid marks, roadway configuration, traffic controls, and the consistency of each person's account can all become important.
Can I recover money if I was partly responsible for the accident?
Potentially, yes. California generally follows a pure comparative-fault system. If your negligence contributed to your harm, your recovery can generally be reduced according to your percentage of responsibility rather than automatically eliminated.
Who has to prove that I was partly at fault?
When a defendant claims that the plaintiff's own negligence contributed to the harm, CACI No. 405 provides that the defendant must prove the plaintiff was negligent and that the plaintiff's negligence was a substantial factor in causing the harm.
What if there was no eyewitness to the accident?
The absence of an eyewitness does not automatically prevent a claim. Other evidence may establish what happened, including photographs, vehicle damage, physical evidence, police reports, video, statements, traffic controls, and reasonable inferences from the surrounding circumstances.
What should I do if I find an error in the police report?
Identify the specific factual error or omission. Depending on the circumstances, it may be appropriate to provide additional information to the investigating agency or request a supplemental report. The important point is to address significant factual inaccuracies rather than simply allowing an incorrect statement to remain unchallenged.
Why should I worry about surveillance video right away?
Some surveillance systems automatically overwrite or delete older recordings. A recording that exists immediately after an accident may no longer exist weeks or months later. If a business, residence, dashcam, doorbell camera, or other system may have captured the accident, identifying that source promptly can be important.
What if the insurance adjuster says I was 20 percent or 50 percent at fault?
That is the insurance company's position during the claim process, not necessarily a final legal determination. Ask the adjuster what facts or evidence support that conclusion. Once the basis for the position is understood, the evidence can be examined to determine whether the conclusion is supported.
What happens if someone sues me for a car accident?
You will be served with a summons and complaint, and you generally have 30 days after service to file a written response with the court. Do not ignore the papers, because a default can be entered against you. Send them to your insurance company right away, since your policy may include a duty to defend. If you have no insurance, speak with a California attorney promptly.
Do I need a lawyer simply because the insurance company disputes fault?
Not necessarily. Some straightforward claims can be handled without an attorney. Legal guidance becomes more valuable when liability is seriously disputed, comparative fault is a significant issue, multiple parties may be responsible, the injuries are substantial or permanent, important evidence needs to be preserved, or the insurance issues become complicated.
What is the most important thing to remember about fault?
Do not assume that fault is settled simply because the answer seems obvious. Preserve the evidence, document what happened, identify witnesses, be accurate about what you know, and understand why the insurance company reaches the conclusions it does. The stronger the evidence, the easier it becomes to evaluate whether the competing versions of the accident are supported by the facts.
The Bottom Line
Fault should not be assumed from one person's perspective. Disputes are normal, and a methodical approach works best.
- Gather evidence and preserve it before it disappears
- Identify witnesses
- Review the police report closely
- Document the physical evidence
- Be truthful about what you know and do not know
- Ask the insurer why it reached its conclusion
If liability is seriously disputed or several parties may be involved, you may want to read Do I Need a Personal Injury Lawyer?. Time limits also apply regardless of how the fault discussion is going, so see California Filing Deadlines. More general questions are answered in the FAQs.
Please remember that laws and regulations can change, and every legal situation is different. Information on this page is for general educational purposes and is not a substitute for legal advice about your particular circumstances.