Before anyone can drive a commercial motor vehicle (CMV), they must receive a commercial driver's license (CDL). Every state has its own requirements for trucking licenses, but there are federal minimum requirement that apply to all states. The driver must be at least 21 years of age and pass a written and driving test. In most states, a CDL is required for all vehicles that weigh over 26,000 pounds and carry 16 or more passengers. There may be additional designations and requirements which vary by state, including hazardous materials transport and driving a school bus. There is a national clearinghouse for CDL records so that no driver can hide traffic infractions from one state to another and to screen drivers applying for a CDL. Traffic infractions can have serious penalties for someone with a trucking license.