What does this sign indicate?

• The route is designated for truck traffic.
  Explanation:

  "This sign indicates a road or path specifically designated for trucks and other heavy vehicles. These routes are planned to accommodate the size, weight, and turning radius of large vehicles and often lead to industrial areas, shipping terminals, or highways."
• The route is closed to all truck traffic.
• Only trucks carrying hazardous materials may use the route.
• All vehicles except trucks are allowed on this route.