Here's an idea that would work well in Courtenay Place:
http://stevewellsphoto.wordpress.com/2008/04/16/cruising/

A sign on the side of the road that says:

No Cruising Zone
Motorists passing the traffic control point 2 or more times in 4 hours are subject to citation

That'd teach those kids a lesson!

The photo is taken by photographer extraordinaire Steve Wells. Formerly of Wellington, now in Paris, and has a great new photo every day on his blog.