Is there a law prohibiting lane straddling in this scenario . I am approaching a cyclist in my car on a four lane city street. I find that the cyclist is ridding too close to the curb and allowing cars to pass him dangerously close. Instead of making a full lane change I decide to left signal and straddle the lanes 50 meters before I reach the cyclist and 50 meters after I have passed him so that no other vehicle can pass between us and put that cyclist at risk.

A cyclist may take the whole lane.

You should move over for the cyclist. You chose to move over a half-lane instead of full.

Now that might be in contradiction with:

"Where highway divided into lanes

154. (1) Where a highway has been divided into clearly marked lanes for traffic,

(a) a vehicle shall be driven as nearly as may be practicable entirely within a single lane and shall not be moved from the lane until the driver has first ascertained that the movement can be made with safety;"

If it is temporary to pass the cyclist, then it should be allowed I think. That's what you would do if that was a single-lane road. Not sure if that was ever proven though .

this is what i do if there is a cop or tow truck in the far left shoulder on the 401 when other idiots are passing without moving over. its a safer in my opinion.