Final answer:
Class A explosives cannot be transported in a combination vehicle if it includes other classes of hazardous materials.
Step-by-step explanation:
In transportation, class A explosives are the most hazardous type of explosive materials. According to the Hazardous Materials Regulations (HMR) of the Department of Transportation (DOT), class A explosives cannot be transported in a combination vehicle if it includes other classes of hazardous materials.
For example, if a combination vehicle is carrying class A explosives along with class B or class C hazardous materials, it would be in violation of the HMR. This is because the risk of an explosion or other accidents would be significantly increased if different classes of hazardous materials are transported together.
Therefore, when transporting class A explosives, it is important to ensure that the combination vehicle does not include any other classes of hazardous materials.