Which vehicles are not allowed to use a road sign-posted like this?

This traffic sign means that motorcycles are not allowed to use the road where this sign is posted. The red circle with the motorcycle symbol inside indicates a prohibition specifically for motorcycles. Cars and trucks are not affected by this sign and are allowed to use the road. This helps regulate traffic by restricting certain vehicle types to maintain safety or reduce noise or pollution in that area. Remember, the sign always refers to the vehicle type shown inside the circle.