What does a diamond-shaped sign on a truck indicate?

• The truck is carrying oversized cargo.
• The truck’s load may be dangerous, such as gas or explosives.
  Explanation:

  "A diamond-shaped sign on a truck indicates that its load may be dangerous (e.g., gas, explosives). Trucks with these signs are required to stop before crossing railroad tracks for safety reasons."
• The truck has the right of way at all times.
• The truck does not need to stop at railroad crossings.