At crosswalks, drivers can go once the pedestrian is clear of the vehicle; otherwise, they may face a $300 fine (doubled in community safety zones) and three demerit points.
Careful. In Ottawa you're risking a fine. Their rules - and it varies by region - is that the pedestrian needs to be out of the crosswalk completely, and not just clear of the vehicle, before the car can continue.
This, as you can imagine, is always a bit of a surprise where it's in place -- especially in Ottawa where they tend to honk if they think you've had the chance to go and waited more than 5 milliseconds.