When is it acceptable to pass a vehicle on the right?

Passing a vehicle on the right is acceptable when the vehicle ahead is turning left and there is sufficient space for you to do so safely. This situation is common in many driving scenarios, especially in urban areas where left turns are made at intersections. When the vehicle in front is signaling its intent to turn left, it provides an opportunity to move around it to the right, provided there is clear space to execute the maneuver without endangering yourself or other road users.

Addressing the other scenarios: passing a vehicle solely based on it moving slower than the speed limit does not justify the action. It is crucial to assess road conditions and surroundings to determine if it is safe to pass, regardless of speed limits. Similarly, poor visibility during rain does not create a safe environment for passing, as it increases the risks associated with maneuvering around other vehicles. Finally, while passing in a parking lot may sometimes be permissible, it is not a generalized rule that applies in most driving situations, making it less applicable compared to the scenario of a left-turning vehicle.