What is the test for a plaintiff to prove that they were injured in a motor vehicle accident?

It is trite law that the onus is on the plaintiff to prove on a balance of probabilities that the accident caused or materially contributed to the plaintiff’s injuries (see Snell v. Farrell, 1990 CanLII 70 (SCC), [1990] 2 S.C.R. 311).

As noted in Athey v. Leonati, 1996 CanLII 183 (SCC), [1996] 3 S.C.R. 458 at paras. 16-17: … The causation test is not to be applied too rigidly. Causation need not be determined by scientific precision … it is essentially a practical question of fact which can best be answered by ordinary common sense. Although the burden of proof remains with the plaintiff in some circumstances, an inference of causation may be drawn from the evidence without positive scientific proof. It is not now necessary, nor has it been ever been, for the plaintiff to establish that the defendantꞌs negligence was the sole cause of the injury. There will be frequently a myriad of other background events which were necessary preconditions to the injury occurring. … As long as the defendant is part of the cause of an injury, the defendant is liable. … [Emphasis in original]