The States and Washington DC are the backbone of Commercial Driver’s Licensing. They issue the licenses and assess the qualifications and validity of each of their drivers. Source: States – Federal Motor Carrier Safety Administration For rules regarding: Certification and Records check: CDLIS (Commercial Driver Licensing Information System), and NDR (National Driver Registry), Self Certification Forms etc. Knowledge and skills test Third party Skills Testing Military Exemptions for Skills Testing Non-domiciled CDL Exemptions, Penalties and more
List of Service Centers and field offices for the FMCSA to answer your questions. These facilities consist of Field Operations, Service center and State-level motor carrier division offices. http://www.fmcsa.dot.gov/mission/field-offices.