Endorsements are required to haul certain types of cargo or to drive a combination vehicle with more than one trailer. Available endorsements are: passenger endorsement – to drive a bus, hazardous material endorsement – to allow transporting hazardous materials in the amount requiring placards, tanker endorsement, double-triple trailers. In order to obtain an endorsement on the CDL license a series of tests must be taken – mostly written. Passenger endorsement also requires an over the road test – driving a bus. Hazardous materials (Hazmat) endorsement requires to go through the background screening.