If you will be transporting hazardous materials that require placards, you must: Question If you will be transporting hazardous materials that require placards, you must: Answers Ask permission of the local law enforcement agency. Obtain a hazardous materials endorsement. Transport the materials only at night. Explanation To operate a vehicle of any size that is used to transport hazardous materials requiring placards, you must have a CDL with a hazardous materials endorsement. This questions appears in the following tests: Kentucky Class B Knowledge Test Louisiana Passenger Nebraska Class A Knowledge Test New Mexico Class A Knowledge Test