Under what condition is it permissible to pass a vehicle on the right?

Passing a vehicle on the right is permissible when the vehicle is making a left turn. This situation presents a clear opportunity for safe passing because the vehicle intending to turn left is signaling its intent to move away from the right lane, creating space for another vehicle to maneuver past it. It's essential that the pass occurs in a location where it's legal to do so, like in a lane designated for travel or in a situation where it's safe to overtake on the right side.

The other conditions would not generally allow for passing on the right safely. For instance, passing a parked vehicle might risk hitting it or not allowing sufficient space for passing. During a red light, vehicles should be stopped, so there would be no need to pass, while narrow roads often lack sufficient space for safe passing. Therefore, the correct context for passing on the right is when the vehicle ahead is preparing to turn left, making it a safe and legally appropriate action.