If you rear-ended someone who stopped suddenly in California, you start out presumed at fault, but that presumption can be beaten. State law requires every driver to keep a following distance that is “reasonable and prudent” for the speed and conditions, so a rear-end impact is treated as evidence you were too close.1California Legislative Information. California Vehicle Code 21703 If you can show the lead driver stopped without a legitimate reason, had broken brake lights, or stopped illegally, fault can shift partially or substantially onto them.
Why You Start Out Presumed at Fault
The following-distance rule is the backbone of nearly every rear-end case. You are expected to leave enough room to react safely to any stop ahead of you, however abrupt.1California Legislative Information. California Vehicle Code 21703 Courts read a rear-end collision as evidence you didn’t.
Lawyers call this a rebuttable presumption. You begin in the hole, but you can climb out with evidence that the lead driver’s conduct made the crash unavoidable. The presumption isn’t a verdict. It just means the burden is on you to show why the usual assumption shouldn’t apply.
When the Driver You Hit Shares the Blame
A sudden stop alone doesn’t make the lead driver negligent. Slamming the brakes because a child darts into the road, or because traffic ahead has halted, is exactly what a driver is supposed to do. The situations that shift fault are different. They involve stops that no reasonable following driver could have anticipated.
Brake Checking
Brake checking is when a driver deliberately slams the brakes to punish or intimidate someone behind them. This is the strongest fault-shifting scenario because the stop served no safety purpose at all. If you can prove the stop was intentional, a significant share of liability moves to the other driver. Without video, these cases often come down to one word against another, which is why dashcam footage matters so much here.
Broken Brake Lights
California requires working brake lights visible from at least 300 feet.2California Legislative Information. California Vehicle Code 24603 If the car in front had burned-out or broken brake lights, you had no visual warning the vehicle was slowing. That equipment failure is evidence of the lead driver’s own negligence and can push a meaningful percentage of fault onto them.
Illegal or Unreasonable Stops
Drivers aren’t allowed to stop on a highway in a way that blocks the normal flow of traffic unless the stop is necessary for safety or required by law.3California Legislative Information. California Vehicle Code 22400 A driver who stops dead on a freeway for no apparent reason, or who swerves into your lane and immediately brakes, may be found negligent. The question a court will ask is whether the stop was reasonably foreseeable to the driver behind.
How California Splits the Damages
California uses pure comparative negligence. You can recover damages even if you were mostly at fault, with your recovery reduced by your share of blame.4Justia Law. Li v. Yellow Cab Co.
The math is straightforward. If your injuries and vehicle damage total $100,000 and the lead driver is found 30% responsible, you can collect $30,000 from their side. It works both directions. If the lead driver’s damages are $50,000 and you’re 70% at fault, you owe $35,000. Each driver pays their share.
What to Do at the Scene
What you do in the first few minutes shapes the whole claim. Check for injuries and call 911 if anyone is hurt. Even if the damage looks minor, California requires you to stop, pull somewhere safe, and exchange your name, address, driver’s license, and insurance information with the other driver.5California Legislative Information. California Vehicle Code 20002 Leaving without doing that is a misdemeanor.
Then start gathering evidence. Photograph both vehicles, the position of the cars before anyone moves them, skid marks, the road surface, traffic signals, and any debris. Take wide shots that show lane markings and sight lines. Get names and numbers from witnesses. The more you document, the stronger your position when an adjuster reconstructs what happened.
One thing people get wrong under stress: don’t say “I’m sorry” or “it was my fault.” Adrenaline makes people apologize reflexively, and those words can be used against you. Exchange information and describe what happened in neutral terms.
Dashcam Footage
Dashcam video is often the single most useful piece of evidence when the lead driver stopped unreasonably or brake-checked you. It captures timing, speed, brake application, and road conditions in a way witness memory can’t match. California allows dashcams but restricts where you can mount them on the windshield, and if your camera records audio you need a visible notice informing passengers.6California Legislative Information. California Vehicle Code 26708 A camera mounted outside the permitted zones can create problems with the footage’s admissibility.
Reports You Have to File
California imposes two separate reporting obligations after a crash, and missing either one creates its own problems.
If anyone was injured or killed, you have 24 hours to file a written report with the California Highway Patrol or the local police department.7California Legislative Information. California Vehicle Code 20008 That’s separate from the 911 call, and officers responding to the scene don’t always generate the formal report that satisfies this requirement.
You also have to file an SR-1 form with the DMV within 10 days if the collision caused any injury, any death, or more than $1,000 in property damage.8California DMV. Report of Traffic Accident Occurring in California The $1,000 threshold is low enough that almost any rear-end collision will meet it. Your insurance agent can file the SR-1 for you. If no one files it, the DMV can suspend your driver’s license.9California DMV. California Driver Handbook – Financial Responsibility, Insurance Requirements, and Collisions
Handling the Insurance Call
Notify your own insurer promptly. Most policies require timely notice, and waiting can give the company grounds to limit coverage. Give them the facts and the police report number if there is one. Keep it factual. Don’t speculate about fault.
When the other driver’s insurer calls, remember that their adjuster works for the company paying the claim, not for you. You are not required to give a recorded statement to the other party’s insurer, and recorded statements often do more harm than good. Small inconsistencies between what you said on tape and what’s in the police report get used to chip away at your credibility. If you talk to them at all, stick to confirmed facts.
If the lead driver’s negligence contributed to the crash, you can file a claim against their liability coverage, and under comparative negligence you can collect your share even if you were mostly at fault. If their coverage falls short or they’re uninsured, your own uninsured/underinsured motorist coverage can fill the gap.
Lawsuit Deadlines If the Claim Doesn’t Settle
When insurance negotiations go nowhere, a lawsuit may be the only path left. California’s deadlines are firm. Miss them and the claim is gone.
- Personal injury claims: two years from the date of the injury.10California Courts. Deadlines to Sue Someone
- Property damage claims: three years from the date of the damage.11California Legislative Information. California Code of Civil Procedure 338
- Claims involving a government vehicle or on-duty government employee: an administrative claim must be filed within six months before any lawsuit can proceed.12Sacramento Superior Court. Government Claims Act
The six-month government deadline is the one that surprises people. It passes quickly while you’re dealing with treatment and repairs, and not knowing the rule isn’t a reason to extend it. If there is any chance the other vehicle was a government car, look into it right away.