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

Passing another vehicle on the right is acceptable specifically when the vehicle in front is making a left turn. In this scenario, the left-turning vehicle creates an opportunity for the driver behind to safely maneuver around it, provided that it can be done without endangering others and within the legal framework.

For instance, if you're approaching a vehicle that is signaling a left turn and there is enough room to pass on the right, you may do so legally and safely as long as there are no obstacles like parked cars or bicycles that would impede this action.

In terms of the other contexts mentioned in the options, passing on one-way streets is not exclusively restricted to the right, as it can also occur on the left since all lanes are moving in the same direction. While passing in a passing zone is permissible, it typically refers to passing on the left whereby specific regulations apply. Lastly, the notion that one should never pass on the right is inaccurate, as there are specific situations, like the one described, where it is appropriate and legal.