The reason why motorcycles are not allowed to travel at high speed on expressways in Shanxi Province is that Article 67 of the Road Traffic Safety Law of the People's Republic of China stipulates that pedestrians, non-motor vehicles, tractors, wheeled special-purpose mechanical vehicles, articulated buses, full-trailer trucks and other motor vehicles with a design top speed of less than 70 kilometers per hour are not allowed to enter the expressway, and motorcycles are motor vehicles, so they are not allowed to enter the expressway.

The speed of the expressway is fast, and there will be safety hazards when motorcycles drive on the expressway. The minimum speed limit of expressway is 60 km/h and the maximum speed limit is 120 km/h, but the maximum speed of motorcycle is usually around 80 km/h, which can't meet this requirement, so motorcycles are not allowed to get on the high speed.