Mann v the Queen

A. Mann had been charged in 1966 with careless driving pursuant to a provincial highway traffic Act. He challenged the constitutional validity of the provincial offence, arguing that Parliament, by establishing an offence of dangerous driving, had made the matter a question of Criminal Law, which according to the Constitution Act, 1867, falls under the exclusive legislative jurisdiction of Parliament.

A majority of the Supreme Court of Canada upheld the constitutional validity of the careless driving provision, stating that the province could legitimately create driving offences that required proof of mere negligence. In their view, the charge of dangerous driving under the Criminal Code required proof of both negligent driving and Mens Rea. In other words, they held that the offence of dangerous driving required proof of advertent negligence, while that of careless driving under the provincial legislation was concerned with inadvertent negligence. However, the court did not define what it meant by "advertent negligence." It is not clear whether the accused must have actual foresight that his or her driving could create a dangerous situation or whether it is sufficient that a reasonable person would have realized the situation was dangerous.