Which action is prohibited regarding driving off-road to pass another vehicle?

Driving onto the shoulder to pass another vehicle is prohibited because the shoulder of the road is designed for emergency situations, not for regular traffic maneuvers. Using the shoulder in this way can create unsafe conditions for both the driver attempting to pass and other road users. The shoulder may not be paved, may have debris, or could accommodate stopped vehicles, all of which pose hazards. It is essential for drivers to remain on the designated lanes of the roadway when attempting to pass, ensuring the safety of everyone on the road.

The other options do not carry the same restrictions. Maintaining a safe speed is a critical aspect of safe driving, and turning the vehicle may be necessary to navigate safely but is not inherently harmful in this context. Additionally, passing on the right can be permissible in certain situations, such as when the vehicle in front is preparing to turn left, provided it’s done safely and without using the shoulder.