A personal injury law rule that lets an injured person recover damages (money) in court, even if their own negligence played a part in causing the underlying accident. The two main variations of this rule are "pure comparative negligence" and "modified comparative negligence."
Around 18 states follow pure comparative negligence, which lets the plaintiff in a personal injury lawsuit recover damages from other at-fault parties, regardless of the plaintiff's share of fault. However, the plaintiff's damages will be reduced by a percentage that's equal to that share of fault. So a plaintiff who's deemed 40 percent at fault for their own accident can only recover 60 percent of their total damages from the other at-fault parties.
About 35 states follow some version of modified comparative negligence, which lets a personal injury plaintiff recover damages in court from other at-fault parties, as long as the plaintiff's share of fault is less than 50 percent (the threshold is 50 percent or less in some states). If the plaintiff's share of fault exceeds the threshold, they can't recover damages in connection with the accident.
Only a handful of states follow a particularly harsh (for plaintiffs anyway) rule called contributory negligence, which usually bars a plaintiff from recovering anything at all in court if their own negligence played a part in causing the underlying accident.