When can drivers pass a streetcar on the left?

Answer: B — When the road is one-way

Passing a streetcar on the left is permissible when the road is one-way. This is because on a one-way street, the lanes are typically designated for movement in a single direction, making it safe to pass the streetcar as long as there are no other hazards or obstacles. The one-way configuration allows for adequate visibility and the absence of oncoming traffic when overtaking the streetcar. In other scenarios, like when the streetcar has stopped, the presence of pedestrians may complicate the situation, thus making it unsafe to pass. Similarly, on a two-way street, passing a streetcar on the left could be dangerous, as there can be oncoming traffic that would make the maneuver risky. Therefore, passing on a one-way street aligns with safety protocols established for traffic laws in relation to streetcars.