Final answer:
Drivers of heavy trucks, particularly those with hazardous materials, must comply with DOT and EPA regulations by having proper documentation like shipping papers and emergency response information. Safety measures also require the truck to be in good condition for descending steep gradients.
Step-by-step explanation:
When operating heavy trucks, especially those carrying hazardous materials, drivers must adhere to strict regulations. According to the United States Department of Transportation (DOT) hazardous materials regulations, as well as the Environmental Protection Agency's (EPA) hazardous waste regulations, drivers must have specific documentation in their possession or on the truck itself. This documentation typically includes shipping papers, permits, emergency response information, and proof of driver certifications.
Additionally, when considering a situation where a truck of mass 1.2 tons is parked at the top of a hill that is 150 meters high, drivers must also be conscious of the safety measures to take when operating such a vehicle on steep gradients. Ensuring the vehicle is in proper mechanical condition to handle the descent and confirming the load is secure are critical precautions. This ties back to the importance of understanding vehicle mechanics and adhering to safety regulations as stipulated by governing bodies like the DOT and EPA.