Which of the following actions is NOT permitted on an express road?

Parking is not permitted on an express road because express roads are designed for the continuous flow of traffic and to ensure safety and efficiency. Stopping or parking on these roads could create dangerous situations, as they are typically used for faster-moving vehicles that require uninterrupted travel. The design of express roads often includes features like specific lanes for overtaking and prohibits actions that might disrupt traffic flow, such as parking or performing U-turns.

In contrast, overtaking on the right is typically not allowed except in specific cases, and making U-turns is generally prohibited as well, reinforcing the need for consistency in traffic flow and safety on express roads. Similarly, driving backwards is also a dangerous maneuver not permitted on such high-speed routes. The overall objective of regulations on express roads is to minimize hazards and maintain efficient traffic movement, which is why parking is particularly restricted.