U-turns

A U-turn is done by turning your vehicle around at an intersection to go in the opposite direction by using oncoming lanes.

This sign means U-turns are not allowed.

Do not do a U-turn unless you can do it safely. U-turns are not permitted:

at an intersection controlled by a traffic control signal (traffic lights) unless permitted by a traffic control device
where a sign prohibits U-turns

In urban areas, U-turns are not permitted:

on a roadway between intersections
at an alley intersection
at an intersection where one or more of the roadways is an access to a public or private parking lot which the public can access

Outside urban areas (rural), U-turns are not permitted:

on a curve
approach to or near the crest of a hill where the driver of another vehicle cannot see you that is approaching within 150 metres from either direction