The short answer
- It comes down to right-of-way. Whoever failed to yield is generally at fault.
- Running a light or stop sign is the most common cause.
- Uncontrolled intersections have their own rules, and they vary by state.
- These crashes tend to cause more serious injury due to limited side-impact protection.
In this guide
A T-bone, or side-impact, collision happens when the front of one vehicle strikes the side of another, most often at an intersection. Unlike a rear-end crash, there’s no single default presumption that applies to whichever position you were in — instead, fault comes down to which driver had the legal right-of-way and failed to yield it.
Right-of-way is the whole question
At a controlled intersection, this is usually the most straightforward version: whichever driver ran a red light or failed to stop at a stop sign is generally at fault, since that’s a direct violation of a clear legal duty. Traffic-camera footage, witness accounts, and the pattern of damage to both vehicles are the typical evidence used to establish who actually had a green light or a clear right-of-way at the moment of impact.
Uncontrolled intersections
Where there’s no signal or stop sign at all — more common in residential areas — right-of-way rules default to specific conventions that vary by state, but commonly follow patterns like whoever arrived or entered the intersection first having priority, or the driver approaching from the right having priority in a genuine simultaneous arrival. These situations are often more genuinely disputed than a signal violation, since there’s no traffic camera or signal timing to settle the question, making witness accounts and the physical evidence more important.
Why T-bone crashes are often more serious
The sides of a vehicle generally have less crumple zone and structural protection than the front or rear, which are specifically engineered to absorb impact before it reaches occupants. A side impact often transfers force more directly, which is a significant part of why T-bone crashes are associated with higher rates of serious injury, including to the head, chest, and pelvis on the side that was struck. This is worth keeping in mind when it comes to documentation and getting checked — an injury from this kind of crash deserves the same prompt, thorough medical attention regardless of how the vehicle damage looks.
Shared fault is common here too
It’s entirely possible for both drivers to bear some responsibility — one running a light while the other was speeding, distracted, or could have reasonably avoided the collision with more attentive driving. Under most states’ comparative negligence rules, this results in a split of fault rather than an all-or-nothing outcome, with your compensation reduced by your own percentage. See our guide on state fault rules for how this works where you are.
Common questions
Who's usually at fault in a T-bone crash?
Whichever driver failed to yield the right-of-way — most often the one who ran a red light or stop sign, or who failed to yield at an uncontrolled or four-way-stop intersection.
What if there's no traffic signal or stop sign at all?
At an uncontrolled intersection, right-of-way rules typically default to whoever arrived or entered first, or to the driver on the right in a genuine tie — but local rules vary, so this is worth checking for your state.
Why are T-bone crashes often more serious?
A vehicle's sides generally have less crumple space and protective structure than the front or rear, so side-impact crashes often transfer more force directly to occupants, which is why injuries tend to be more severe.
Can both drivers be found at fault?
Yes — if one driver ran a light but the other was speeding or distracted and might otherwise have avoided the crash, fault can be split between both under most states' comparative negligence rules.
Sources
Written by The Accident Advisory editorial team from the sources below. Every change is logged in the editorial changelog.
- State DMV consumer resources — intersection right-of-way rules (varies by state). Accessed
- National Highway Traffic Safety Administration (NHTSA) — side-impact crash safety information. nhtsa.gov. Accessed
The Accident Advisory provides free, general information and is not a law firm and does not provide legal advice. Fault determination depends on the specific facts of your case and the law of your state. This guide is for informational purposes only.