What does this sign mean?

• This road is prohibited for long commercial vehicles.
• Any vehicle carrying hazardous substances or toxins is prohibited on this road.
  Explanation:

  "This sign indicates that any vehicle carrying hazardous substances or toxins is prohibited from using this road for the safety of the environment and the public by preventing potential spills or accidents involving dangerous materials."
• Vehicles must stop for inspection before entering this road.
• Only emergency vehicles are allowed on this road.