Highways should adopt the same clear height. The clear height of expressway, first-class highway and second-class highway should be 5.00 m; The clear height of Grade III and IV highways shall be 4.50m. ..
Extended data:
According to China's People's Republic of China (PRC) Highway Law,
Article 50? Vehicles exceeding the load, height, width and length limits of highways, highway bridges, highway tunnels or car ferries are not allowed to run on roads, highway bridges or highway tunnels with limited standards, and car ferries are not allowed to be used.
If it is really necessary to drive beyond the load limit standard of roads or highway bridges, it must be approved by the transportation department of the local people's government at or above the county level and take effective protective measures as required; Those who carry indissoluble and out-of-gauge articles shall drive at the prescribed time, route and speed, and hang obvious signs.
If the transport unit cannot take protective measures in accordance with the provisions of the preceding paragraph, the transportation department shall help it to take protective measures, and the expenses required shall be borne by the transport unit.
Baidu Encyclopedia-People's Republic of China (PRC) and National Highway Law