What are defenses to negligence?

Aside from failing to meet the elements of negligence, not all accidents result in compensable injuries. If an accident cannot be avoided even if reasonable care is taken, then negligence cannot be proven - for instance, if a driver has an unexpected seizure and causes an accident, negligence cannot be proven unless the driver had reason to expect the seizure. Acts of God also fall under cases in which negligence cannot be proven; likewise, assumption of risk is a proper defense, i.e., a victim sustained injuries as a result of a relationship or transaction they entered with full knowledge and acceptance of the risks commonly associated with such undertakings.