Comparative negligence is a term that defines a responsibility on both parties in an incident. When two parties are both negligent in some way, the damages being sought will be lowered somewhat to account for that negligence. For instance, if one vehicle hits another vehicle, he or she may be liable for damages. However, if the second vehicle did not have his or her headlights on, the damages may be lower than they would normally be had the headlights been on. Comparitive negligence allows courts to be fair and forces all responsible parties to pay for their actions. In most cases, facts must be proven before the comparitive negligence statute takes affect. For instance, it would have to be proven that the second car did not have the headlights on. This might be done with witnesses or police reports.