What type of materials, when transported in a vehicle, necessitate a CDL?

The correct answer focuses on "hazardous materials requiring placards." When transporting hazardous materials, a Commercial Driver's License (CDL) is mandatory due to the significant risks associated with these materials. These risks include potential leaks, exposure to toxic substances, and the need for specialized training to handle emergencies that can occur while transporting such materials. The requirement for placards indicates that other drivers and emergency responders need to be aware of the potential dangers on the road, underscoring the importance of having a driver trained and certified to transport these items safely.

In contrast, while heavy construction materials and perishable items may require careful handling and can be heavy, they do not necessarily require a CDL unless they reach specific weight thresholds or other regulatory criteria. Fragile goods, although they need careful transportation to avoid damage, also do not invoke the same safety requirements that hazardous materials do. Therefore, only hazardous materials necessitate the specialized training and licensing provided by a CDL.