The Superior Court of Pennsylvania has held per curiam that Pennsylvania's comparative negligence statute is to be applied only to causes of action arising on or after the statute's effective date, and that the doctrine of contributory negligence continues to govern all causes of action in negligence which arose prior to that date.
Costa v. Lair, 241 Pa. Super. Ct. 517, 363 A.2d 1313 (1976).
Linda J. McClellan,
Torts - Comparative Negligence Statute - Prospective Application of Statutes,
Duq. L. Rev.
Available at: https://dsc.duq.edu/dlr/vol15/iss3/10