A Newmarket judge dismissed stunt driving charges against an 18-year-old woman who had been caught doing 157 kilometres per hour on Highway 407 north of Toronto.

Fifty kilometres an hour over the posted speed limit is considered speed racing or stunt driving under the law introduced in 2007.

Justice Peter West ruled that having a potential penalty of up to six months in jail violates the Charter of Rights because the law does not allow the accused to present a defense.

It's the second time a provincial court has struck down the law as unconstitutional, and the first case is scheduled to be heard by the Court of Appeal in the new year.

The Attorney General's ministry said in an e-mail that its position is that “the street racing provisions are Constitutional and they are an important public safety initiative.”