It must be proven that there is a direct causal relationship between the insured person's impairments and the use or operation of the vehicle in question (the «
chain of causation test» or, simply, the «causation test.»)
The Ontario Court
of Appeal's Aristorenas at para. 53 was a good start: «The
test is invoked because
of logical or structural difficulties in establishing «but for»
causation, not because
of practical difficulties in establishing that the negligent act was a part
of the causal
chain.»