The accident occurred in 2004, when Joseph Clements lost control of his motorcycle in wet weather while driving from Prince George to Kananaskis, Alta., with his wife Joan riding behind on the passenger seat.
According to court documents, the bike was overloaded and unknown to the couple, a nail had punctured the back tire. When Joseph accelerated past the speed limit to overtake another vehicle, the nail fell out, deflating the tire and Clements lost control of the bike.
The case could affect the way negligence cases are dealt with, and hinges on the "but for" causation, which requires that but for a defendant's negligence, a plaintiff would not have been injured.
In the Clements case, a Vancouver trial judge ruled in 2009 that it was impossible to prove "but for" causation, citing a lack of scientific reconstruction evidence.
Despite this, the trial judge went on to find Joseph Clements negligent, based on how much of a "material contribution" to the risk of injury his actions had made.
In 2010, the Court of Appeal for British Columbia overturned that judgment and dismissed the case, on the basis that "but for" causation had not been proved and the "material contribution" test did not apply.
However, on Friday, the Supreme Court ruled by majority that the trial judge ruled in error, stating not only that the "material contribution" test was inapplicable but also that scientific precision was not necessary to prove "but for" causation.
The "material contribution" test is only exceptionally applied in cases where it is unclear which of a number of defendants was responsible and where required to provide due "compensation, fairness and deterrence."
One of the first cases to use such a test occurred in 1951, when a man was inadvertently shot on a hunting trip by one of two friends, who fired their guns at the same time. Both were found jointly negligent as a result of the "material contribution" test.Suggest a correction