A delivery van with a driver and a passenger wants to use an HOV lane. Is meeting the two-person requirement enough?

Correct answer: C. No — a commercial motor vehicle must also be less than 6.5 metres in total length, and large trucks are barred whatever the occupancy

Not on its own — commercial vehicles face a length test as well. The Driver's Handbook says "commercial motor vehicles must have two or more people in the vehicle and be less than 6.5 metres in total length to be in the HOV lane", and it is blunt about the larger ones: "large trucks are not permitted on the HOV lanes, regardless of the number of occupants." The rest of the eligibility list is generous by comparison — buses at any time regardless of occupants, emergency vehicles, licensed taxis and airport limousines even with a single occupant, motorcycles, and green-plate vehicles with any number of people aboard. One rule applies to everyone in or out of the lane: "the HOV lane is separated from the other general traffic lanes by a striped buffer zone. It is illegal and unsafe to cross the striped buffer pavement markings."

Source: MTO Driver's Handbook: Official MTO Driver's Handbook — Freeway driving, High Occupancy Vehicle (HOV) lane