To establish negligence and thus fault in an Alberta motor vehicle claim there are four elements of the case. In this blog we will discuss the third element – causation. The first two are: 1) Duty and 2) Breach of the Duty. In a motor vehicle collision, the first element, duty, is almost always assumed as, by virtue of driving on a highway, you owe a duty to other motorists to take care. The second element breach of the duty is often contested. However we will focus on the third element causation. Only after establishing causation does one go on to the fourth element of a negligence case: damages.
The plaintiff does not have to establish that the motor vehicle accident was the sole cause of the injury or death
To quote the leading case on causation from the Supreme Court of Canada, Athey v Leonati  3S.C.R. 458, J. Major summarizes the law of causation.
J. Major in Athey states that “it is not now necessary, nor has it ever been, for the Plaintiffs to establish that the Defendant’s negligence was the sole cause of the injury. There will frequently be a myriad of other background events which were necessary pre-conditions to the injury occurring . . . As long as the Defendant is part of the cause of the injury, the Defendant is liable, even though his act alone was not enough to create the injury. There is no basis for a reduction of liability because of the existence of other pre-conditions: Defendants remain liable for all injuries caused or contributed to by their negligence. . . The law does not excuse the Defendant from liability merely because other causal factors for which he is not responsible also helped to produce the harm.”
Another leading decision from the Supreme Court of Canada on causation is Laferriere v Lawson  1S.C.R. 541 where J. Gonthier for the majority made the following summary of the principles governing determination of causation.
“Cassation in law is not identical to scientific causation.”
“Causation in law must be established from the balance of probabilities, taking into account all of the evidence: factual, statistical and that which the Judge is entitled to presume.”
“In some cases, where a fault presents a clear danger and where such a danger materializes, it may be reasonable to presume a causal link, unless there is a demonstration or indication to the contrary.”
In 1974, the Supreme Court offered that “it is not necessary that one foresee the precise concatenation of events. It is enough to fix liability if one can foresee in a general way the class or character of injury which occurred” (R. v. Cote).
In 2007, Canada’s Supreme Court thought it would help the state of the law with this statement in Resurfice v Hanke:
“(I)n special circumstances, the law has recognized exceptions to the basic but for test, and applied a “material contribution” test. Broadly speaking, the cases in which the “material contribution” test is properly applied involve two requirements.
“First, it must be impossible for the plaintiff to prove that the defendant’s negligence caused the plaintiff’s injury using the but for test. The impossibility must be due to factors that are outside of the plaintiff’s control; for example, current limits of scientific knowledge. Second, it must be clear that the defendant breached a duty of care owed to the plaintiff, thereby exposing the plaintiff to an unreasonable risk of injury, and the plaintiff must have suffered that form of injury. In other words, the plaintiff’s injury must fall within the ambit of the risk created by the defendant’s breach. In those exceptional cases where these two requirements are satisfied, liability may be imposed, even though the but for test is not satisfied, because it would offend basic notions of fairness and justice to deny liability by applying a but for approach”.
For example if a man died one month after a motor vehicle collision from a “cause” not directly related to the injuries in the collision, this does not relieve the wrongdoer from liability. A chain of causation could look like this: a man died from blood poisoning, which was caused by an infection from catheterization, which was necessary because of urinary retention, which was caused by the narcotic drug given to him, which was necessary because of the severe back pain he suffered in the motor vehicle collision. The chain of causation could not be clearer. The plaintiff does not have to establish that the motor vehicle accident was the sole cause although in this example one can argue that the motor vehicle accident was the sole cause, in that, absent the motor vehicle accident he would not have had blood poisoning and died on the date that he died.
As J. Major said in the Supreme Court of Canada there will always be a myriad of other factors but that does not create the basis for removing liability or creating a situation of non-causation such that the Defendant will be absolved of liability.
Handel Law Firm is Alberta’s personal injury law firm serving the smaller communities of Red Deer, Lethbridge, Medicine Hat, Fort McMurray and Grande Prairie. Call now Toll Free: 1-877-844-6910