If you were just T-boned, or you were the one who struck someone from the side, your head is probably still spinning from the impact and from the uncertainty of what happens next. One of the first questions that surfaces, sometimes before the adrenaline has even worn off, is who is going to be held responsible for this. The answer is rarely as obvious as it seems from where you’re sitting, and the assumptions most people carry into that question can actually hurt them before a lawyer, an adjuster, or a jury ever gets involved.
A T-bone collision, also called a broadside or side-impact crash, happens when the front of one vehicle strikes the side of another, forming the shape of the letter T. These crashes typically happen at intersections, in parking lots, or when one driver pulls out of a driveway or side street. They are among the most dangerous collisions on the road because the side of a car offers far less protection than the front or rear, and the occupants nearest the point of impact absorb an enormous amount of force. The severity of the crash is part of why fault matters so much. T-bone accidents produce serious injuries, and serious injuries produce substantial insurance claims and lawsuits.
The instinctive assumption people make is that the driver who physically struck the other vehicle from the side is the one at fault. That logic feels clean. You hit me, you pay. But fault in a T-bone accident is determined by who had the legal right of way, not by the geometry of the collision. The car whose front end did the damage may have done nothing wrong. The car that got hit may have caused the entire thing by running a red light, failing to yield at a stop sign, or pulling into traffic without looking. So before you assume anything about your situation, set aside the physical picture of the crash and think about what the law required each driver to do at the moment before impact.
At a controlled intersection, meaning one with traffic signals, fault almost always falls on the driver who entered against a red light. If you had a green light and someone crossing your path ran their red, you almost certainly had the right of way, and they are almost certainly responsible. At an uncontrolled intersection or a two-way stop, the driver who was required to stop and yield carries the burden of proving they did so before proceeding. At a four-way stop, whoever arrived first had the right to go first, and if two vehicles arrived simultaneously, the driver on the left is required to yield to the driver on the right. These are the foundational rules, and they apply across virtually every state in the country.
Where things get complicated is in the gap between what the rules say and what can actually be proven. The other driver will very often claim the light was green for them too. They will say you ran the stop sign. They will say they had already cleared the intersection when you came out of nowhere. People involved in crashes are not necessarily lying when they say these things. Adrenaline, shock, and the brain’s tendency to fill gaps in perception with plausible narrative mean that two drivers can experience the same collision with genuinely different memories of it. What matters, then, is evidence, and the evidence that resolves T-bone disputes is often collected in the first hours and days after a crash, or it disappears forever.
Traffic camera footage is the most definitive evidence available in most intersection collisions, but it is not preserved automatically. City traffic management systems and private cameras on nearby businesses typically overwrite their recordings on loops of anywhere from 24 hours to 30 days. If your attorney or a representative from your side does not send a written preservation demand to the relevant city department or business within days of the crash, that footage is almost certainly gone. This is not a small thing. It is the difference between having proof and having a word-against-word fight with an insurance company that is professionally experienced at winning word-against-word fights.
Traffic signal timing data is something almost no one outside the legal and engineering world thinks to request, and it is one of the most underused pieces of evidence in intersection crash cases. Every modern traffic signal controller logs its own cycle history, recording exactly when each light was green, yellow, or red and for how long. When the physical timing of the collision is known from other sources, this log can confirm or destroy either driver’s account of who had the light. This data is maintained by city or county transportation departments and, like camera footage, has a short retention window. A formal preservation request needs to go out fast. Most people never know this data exists. The attorneys who know to ask for it win disputes that look unwinnable on paper.
Event data recorders, commonly called black boxes, are present in virtually all vehicles manufactured after 2000 and are required by federal regulation to meet certain standards in vehicles built after 2014. In a crash that meets a certain force threshold, the recorder captures pre-crash vehicle speed, throttle position, brake application, steering input, and whether seatbelts were in use. This data is stored on a chip inside the vehicle and can survive the crash itself. It can confirm whether a driver was braking before impact or had never touched the brake at all. It can show a speed that contradicts what the driver claims they were doing. Critically, this data can be overwritten if the vehicle is started again after the crash, and the physical recorder can be lost if the vehicle is sent to a salvage yard and crushed. A legal hold letter to the other party’s insurance company and potentially a court order are the tools used to preserve this evidence, and they need to move quickly.
Witness statements are valuable but perishable in a different way. People who saw the crash from a sidewalk, a nearby vehicle, or a business window have clear, detailed memories in the first hours. Those memories degrade. Their willingness to get involved diminishes as time passes and as the inconvenience of being contacted again and again becomes apparent. If you were able to get names and numbers at the scene, that matters. If you were not, your attorney or an investigator working on your behalf may be able to canvass the area, review nearby businesses for employees who saw the crash, or identify other vehicles in the area using traffic camera footage that shows them even if it doesn’t show the collision itself.
Missouri follows a system of pure comparative fault, which means that even if you are found partially responsible for the crash, you can still recover damages reduced by your percentage of fault. If a jury decides the other driver was 80 percent at fault and you were 20 percent at fault for speeding, you recover 80 percent of your total damages. Many states use a modified version of this rule that cuts off recovery entirely if you are more than 50 percent at fault. Knowing which system applies in your state matters because it shapes how aggressively the other side’s insurance company will try to assign you partial blame. In a pure comparative fault state like Missouri, even a driver who was mostly at fault can still recover something, which gives the insurance company less incentive to pin everything on you but also less reason to offer you a fair settlement when they can reduce it by inflating your share of fault.
Left turns are worth addressing specifically because they generate a disproportionate share of T-bone accidents and they carry a very clear default rule in most situations. A driver making a left turn through an intersection is required to yield to oncoming traffic. If you were turning left and got hit from the side by a driver coming straight through, the initial presumption is that you failed to yield. Overcoming that presumption requires showing that the oncoming driver had a red light, was traveling at an illegal speed that made them impossible to anticipate, or that some other circumstance shifted the right of way. It can be done, but it requires evidence, and the burden of producing it is on you.
Parking lot T-bones operate under slightly different rules because there are no traffic signals and no formal right-of-way doctrine governing most private lots. Courts and insurers typically look at which driver had a stop sign if one was present, which driver was moving from a parked position into a travel lane, and general principles of reasonable care. Parking lot speeds are low enough that these crashes are less often catastrophic, but they are common and the fault disputes can be just as contentious because both drivers frequently believe they had the right to proceed.
The practical takeaway from all of this is that fault in a T-bone accident is a factual and legal determination that depends on what can be proven, not just on what happened. Evidence that exists today will often not exist next week. The driver who moves quickly to preserve traffic footage, request signal timing data, secure the event data recorder, and lock in witness statements is in a fundamentally stronger position than the driver who waits to see what the insurance company comes up with. Insurance companies are not neutral arbiters of fault. They have a financial interest in the outcome of that determination, and they know how to work with incomplete evidence. Your job right now is to make sure the evidence that supports your account does not disappear before anyone gets a chance to use it.
This article is intended for general informational purposes only and does not constitute legal advice. Laws governing fault, comparative negligence, and evidence preservation vary by state and by the specific facts of each case. If you have been involved in a T-bone accident, you should consult a licensed personal injury attorney in your jurisdiction as soon as possible to protect your rights and preserve critical evidence before it is lost.