Rear-end collision fault: the presumption, the rebuttals, and what comparative negligence costs you.

The legal presumption

Every state codifies a following-distance duty. NHTSA crash causation data attributes more than 87 percent of rear-end crashes to driver inattention or following too closely. Courts and insurers translate that into a rebuttable presumption: if you hit the car in front of you, you were following too closely or not paying attention, and you owe the damages.

What rebuts the presumption

• Sudden unsafe lane change. Front car cuts in with insufficient gap. The lane-change driver becomes the at-fault party.
• Brake-check or road rage stop. Hard to prove without dashcam or independent witnesses.
• Non-functioning brake lights. Inspection-station records, photographs, or post-crash examination shift partial fault.
• Chain reaction. A third vehicle pushes the middle car into yours; liability tracks to the originating driver.
• Reversing. Front driver reverses into a stopped rear car; fault flips entirely.

What comparative negligence does

The three U.S. systems and what they mean for a rear-end claim where you bear some fault:

The four contributory-negligence states are the most consequential trap in rear-end claims. A 5 percent share of fault zeroes the claim. Settlement strategy in those states is fundamentally different.

Evidence that holds up

1. Scene photographs before vehicles move, especially showing the position of debris and tire marks.
2. Dashcam footage from any involved vehicle.
3. Witness names and phone numbers, captured at the scene.
4. Event data recorder (EDR or "black box") data, preserved within 30 days where possible.
5. The police report and any supplemental investigation.