A grader is working slowly along your side of a rural road, and a worker in a vest steps out and waves you around it, onto the gravel shoulder. Passing by driving off the roadway is normally prohibited. May you go?

Correct answer: D. Yes — a worker on the maintenance operation directing you past a road service vehicle is a specific exception, if it is safe

Yes — provided you can do it safely. HTA s.150(2) is the general ban: "No driver of a motor vehicle shall overtake and pass another vehicle by driving off the roadway." Section 150(3)(f) then makes an exception for "a motor vehicle overtaking and passing to the right of a road service vehicle or road-building machine where a person apparently employed by or on behalf of the authority that is engaged in the highway maintenance operation has directed the driver to pass it and the movement can be made in safety." Two conditions have to hold at once: someone working on the operation has actually directed you past, and it is safe. Neither alone is enough — a wave from a worker does not excuse an unsafe pass, and a clear shoulder does not excuse passing without being waved through.

Source: MTO Driver's Handbook: HTA Section 150(2) and (3)(f) — passing a road service vehicle when directed by a worker