What is the test for pendent jurisdiction in a motor vehicle accident case?

The origin of the concept of pendent jurisdiction was, as the majority notes, the serious problems of judicial administration which resulted from the existence of separate federal and state claims for the same injury. If the state claim could not be tried in a federal court when substantially identical federal claims were tried there, in many cases there would have been a complete duplication of the effort of litigation in the state courts. The alternative to such duplication would have been an untoward extension of the doctrine of res judicata to require the plaintiff to forego his state claim if he litigated and lost in the federal courts, despite the fact that the federal courts never purported to have jurisdiction of the state claim. Hurn v. Oursler, 1933, 289 U.S. 238, 53 S.Ct. 586, 77 L.Ed. 1148, was the basic solution to the dilemma, and the bedrock on which it rested was that without "pendent" jurisdiction the state claim could not have been tried at all in the federal forum.