Though the Department of Transportation plays a major role in most transportation issues, it takes a hands-off stance when it comes to driver's licenses and vehicle registration laws. These, instead, are handled by individual state governments and their respective motor vehicle offices.

Most driver license regulations are similar in scope, but generally differ in fees, education requirements and driving restrictions on permits and junior licenses. This also applies to titling and registration laws. Some states, for instance, stagger annual registrations throughout a calendar year, while others base it alphabetically on a driver's last name. You can learn the rules for your state by consulting a driver's manual or calling your local motor vehicle office.

Commercial driver's licenses (CDL) are also administered by state governments. However, drivers transporting hazardous materials must adhere to federal regulations in obtaining a hazmat endorsement. This requires passing fingerprint-based background checks.

All but New Hampshire and Wisconsin impose driver responsibility laws, requiring carrying liability insurance. Minimum coverage amounts, however, do vary by state.

Buses and trains that carry passengers across state lines are federally regulated. Whereas buses, taxis, transport vans and limousines that stay within state borders are governed by the state, and, in some instances, the towns from which they operate from.