What is the test for determining liability of a defendant in a motor vehicle accident?

To establish liability on the part of a defendant, causation must be established on a balance of probabilities. The issue is whether the tortious conduct on the part of the defendants (or either of them) caused or contributed to the injuries sustained by the plaintiff. If so, then the breach of duty is causally connected to such injuries. As Sopinka J. observed in Snell v. Farrell (1990), 1990 CanLII 70 (SCC), 72 D.L.R. (4th) 289 at 298 (S.C.C.): Causation is an expression of the relationship that must be found to exist between the tortious act of the wrongdoer and the injury to the victim in order to justify compensation of the latter out of the pocket of the former.