If someone runs a red light and you hit them, the driver who ran the light is almost always at fault. Traffic law gives the right-of-way to the driver with the green, and blowing through a red is one of the cleanest violations an insurer or jury can evaluate. The complication is on your side of the wheel: if you were speeding, distracted, or had time to brake and didn’t, the other driver’s insurer will argue you share some of the blame, and depending on your state that argument can reduce or even eliminate what you recover.
Why the Red-Light Runner Starts Out at Fault
Every state requires drivers to stop at a red light. When a driver violates that rule and causes a crash, courts apply a doctrine called negligence per se, which treats the traffic violation itself as proof of negligence. You don’t have to separately argue the other driver was careless; the fact that they broke the law does most of the work. What’s left for a jury is whether the violation actually caused the collision and your injuries.1Legal Information Institute. Negligence Per Se
The principle traces back to Martin v. Herzog, where the New York Court of Appeals held that an unexcused violation of a safety statute “is negligence in itself,” not merely evidence of negligence.2vLex. Martin v Herzog Because traffic signals exist specifically to prevent intersection collisions, running one and causing a crash is exactly the kind of statutory breach that triggers the doctrine.
In practice, this shifts the conversation. Instead of debating whether the red-light runner was “being careful enough,” the discussion jumps straight to causation and damages. The runner starts at a severe disadvantage, and absent a compelling excuse, they carry the liability.
When You Could Still Share Some of the Blame
A green light is not a shield. If you were doing 50 in a 35, looking at your phone, or watched the other car coming for seconds before impact without touching the brake, expect the other side to argue you contributed to the crash. Three fact patterns come up repeatedly:
- Speeding through a green. A green light doesn’t license you to drive 60 in a 30. If you were well over the limit, the other side will argue your speed made the collision unavoidable or much worse than it had to be. A jury can realistically assign you 20 or 30 percent of the fault for that.
- Not reacting when you could have. If physical evidence shows the other car was in the intersection long enough that an attentive driver would have braked or swerved, your reaction time becomes part of the story.
- Turning left on a green. Left-turning drivers are usually at fault when they hit oncoming traffic because they must yield. The exception is when the oncoming car ran a red, but the other driver will almost certainly claim they had a green. Without a camera, dashcam, or credible witness, that fight is uphill.
Whether any of this actually costs you money depends on how your state divides fault between drivers.
How Your State’s Fault Rules Change the Outcome
Comparative Negligence States
Most states use some form of comparative negligence, which divides fault by percentage and reduces your recovery accordingly. If a jury decides you were 20 percent at fault for speeding and the red-light runner was 80 percent at fault, your compensation drops by 20 percent.
Two versions exist. Under pure comparative negligence, you can recover something even if you were mostly at fault, though your award shrinks by your share of the blame. Under modified comparative negligence, there’s a cutoff. Some states bar you from recovering if you’re 50 percent or more at fault; others set the bar at 51 percent.3Legal Information Institute. Comparative Negligence The practical difference is sharp: in a 50 percent bar state, a 50/50 split means you walk away with nothing. In a 51 percent bar state, at the same split, you still collect half your damages.
Contributory Negligence States
Four states and the District of Columbia still follow pure contributory negligence: Alabama, Maryland, North Carolina, and Virginia. In those jurisdictions, any share of fault at all bars you from recovery. Even one percent of blame for being slightly over the speed limit can wipe out an entire claim. If you live in one of these places and you hit someone who ran a red, keeping your own driving above reproach at the moment of impact is central to the case.
The Last Clear Chance Doctrine
Some contributory negligence jurisdictions keep an escape hatch called “last clear chance.” If you were partly negligent but the other driver had a final opportunity to avoid the crash and didn’t take it, you can still recover.4Legal Information Institute. Last Clear Chance The doctrine cuts both ways. The red-light runner’s attorney can argue that you had the last clear chance to avoid the collision by braking or swerving, even with a green light. Cases like that turn on seconds and reaction times.
No-Fault States
About a dozen states use a no-fault system, including Florida, Michigan, New York, and Pennsylvania. In those states, your own insurance covers your medical bills and lost wages through personal injury protection regardless of who caused the crash. You can only step outside that system and sue the other driver if your injuries clear a threshold set by state law, either a dollar amount or a severity standard. No-fault doesn’t make fault irrelevant: it still governs property damage, and it still governs serious-injury claims that exceed the threshold. If a red-light runner seriously hurts you in a no-fault state, a full liability claim against them is generally still on the table.
Situations That Make Fault Harder to Sort Out
Yellow-Light Disputes
Some of the hardest cases involve a driver who claims the light was still yellow when they entered the intersection. Drivers are allowed to proceed through a yellow if they can’t safely stop before the stop line. The fight becomes whether the signal was yellow or red at the moment the driver crossed. Without camera footage, these cases often turn on witness credibility and accident reconstruction. Signal timing data from the traffic department can be decisive.
Unprotected Left Turns
If you were turning left on a green and an oncoming driver ran a red, the red-light runner carries fault despite the general presumption against left-turners. Proving it typically requires objective evidence, because the other driver will almost always insist they had a green.
Speeding Through a Green
If you were significantly above the speed limit when you hit a red-light runner, expect the other side to argue your speed changed the physics of the crash. In a comparative negligence state, a jury finding of 20 or 30 percent against you reduces your award by that same percentage.
Evidence That Settles Who Ran the Light
Red-light cases hinge on proof of the signal status at the moment of impact. The driver who ran the light will rarely admit it, so independent evidence is what moves a claim.
Police reports are the foundation. Officers document the time, location, weather, road conditions, and witness statements, and many reports include a diagram showing vehicle positions, direction of travel, and signal locations. Reports aren’t gospel, but insurers and courts treat them as serious evidence.
Red-light cameras, where they exist, provide the cleanest proof. These automated systems photograph vehicles entering intersections after the light turns red, usually capturing the plate, timestamp, and signal phase. Dashcam footage from either vehicle or a nearby car can settle the dispute outright, and surveillance cameras on nearby businesses sometimes capture intersection crashes as well. If you suspect a business camera recorded the collision, move fast. Many systems overwrite footage within days or weeks, and an attorney can send a preservation letter that creates a legal duty not to destroy it.
Physical evidence also tells a story. Skid marks indicate braking patterns and can reveal whether a driver tried to stop. The location and angle of vehicle damage helps reconstruct each car’s trajectory. Debris fields show the point of impact. Traffic engineers can analyze signal timing records to determine exactly when the light changed, which is critical in yellow-light disputes.
One warning on your own conduct at the scene: avoid admitting fault or speculating about what happened. Saying “I’m sorry, I didn’t see you” out of politeness can land in an adjuster’s notes as an admission. Stick to the facts when speaking with the other driver and the responding officer.
What the Red-Light Runner Faces Beyond the Insurance Claim
Red-light violations carry fines that range widely by jurisdiction, from under $100 to several hundred dollars, plus points on the driver’s record that can trigger a license suspension if they accumulate. Penalties are generally steeper when the violation caused a crash.
When running a red light causes serious injury or death, the driver can face criminal charges beyond a traffic ticket, including reckless driving, vehicular assault, or vehicular manslaughter depending on the circumstances and jurisdiction. Aggravating factors like intoxication, excessive speed, or a history of traffic violations make criminal prosecution more likely.
On the civil side, the at-fault driver is personally liable for damages that exceed their insurance policy limits. If your medical bills, lost income, and other losses run past the policy, you can pursue the driver’s personal assets. Damages typically include medical expenses, rehabilitation, lost wages and reduced earning capacity, vehicle repair or replacement, and pain and suffering. Some states also allow punitive damages when the behavior was especially reckless.
The Deadline That Can End Your Case Before It Starts
Every state imposes a statute of limitations on injury and property damage claims. Miss the deadline and you lose the right to sue, regardless of how strong the facts are.
For personal injury claims from a car accident, most states set the deadline at two or three years from the date of the crash, though a few allow as little as one year and others go as long as six. Property damage deadlines follow a similar pattern, running from two to six years depending on the state.5Justia. Civil Statutes of Limitations 50-State Survey Courts almost never extend these deadlines simply because a plaintiff didn’t know about them.
Insurance policies impose their own, often shorter, reporting deadlines. Many require you to notify your insurer within a specific number of days, and waiting months to file can give the company grounds to deny coverage. Report the crash to your own insurer promptly, and if you were injured, talk to an attorney well before the statutory clock runs down.