Vehicles transporting cylinders over 1000 lb must be labeled according to which regulations?

Vehicles transporting cylinders over 1000 lb must adhere to DOT (Department of Transportation) regulations, which are specifically designed to ensure safety during the transport of hazardous materials, including propane cylinders. The DOT regulations outline the labeling, packaging, and handling requirements for various types of hazardous materials, including the necessity for appropriate labeling of vehicles transporting gas cylinders to inform first responders and the public about the potential hazards involved. This information is crucial for safety during transportation and in the case of an emergency.

While other options refer to various safety and transportation guidelines that may apply in different contexts, DOT regulations are the primary authority governing the transportation of hazardous materials across state lines, making them the correct choice for this question.