CDL

A Commercial Driver's License (CDL) is a driver's license required in the United States to operate any type of vehicle which has a gross vehicle weight rating (GVWR) of 26,001 lb (11,793 kg) or more for commercial use, or transports quantities of hazardous materials that require warning placards under Department of Transportation regulations, or that is designed to transport 16 or more passengers, including the driver. This includes (but is not limited to) tow trucks, tractor trailers, and buses.
The Commercial Motor Vehicle Safety Act of 1986 was signed into law on October 27, 1986. The primary intent of the Act was to improve highway safety by ensuring that truck drivers and drivers of tractor trailers and buses are qualified to drive Commercial Motor Vehicles (CMVs), and to remove drivers that are unsafe and unqualified from the highways. The Act continued to give states the right to issue CDLs, but the federal government established minimum requirements that must be met when issuing a CDL.
http://www.cdltestgenius.com

The Commercial Driver's License Information System (CDLIS) and the National Driver Register (NDR) exchange information on traffic convictions and driver disqualifications of commercial drivers. States have to use both CDLIS and NDR to check a driver's record before a CDL can be issued. To gain permission to access to the CDLIS and NDR databases one should visit the Federal Motor Carrier Safety Administration (FMCSA) Technical Support Web site for instructions on how this information is accessed and who can access it. Trucking companies can use a commercial service that has clearance for providing this information as a means of screening prospective employees.

In the United States, training may be obtained by completing a qualified CDL training program through a truck driving school. These training programs specialize in teaching potential truck drivers the necessary skills and knowledge to properly and safely operate a truck, including map reading, trip planning, and compliance with Department of Transportation laws, as well as backing, turning, hooking a trailer, and road driving. The overall purpose of these training schools is to help truckers-to-be pass the CDL knowledge and skills tests as well as advanced driving techniques such as skid avoidance and recovery and other emergency actions for situations such as a break away trailer and hydroplaning. These classes usually go well beyond the training the typical non-commercial driver receives, such as the drivers education provided in high school.
There are a number of licensed CDL training schools around the United States, and many trucking companies operate their own schools as well.

The medical standards for drivers of commercial vehicles are set by the National Transport Commission and AUSTROADS, and are set out in 'Assessing Fitness to Drive' (available from the AUSTROADS website).
For those applying for heavy vehicle licence classes MR (Medium Rigid), HR (Heavy Rigid), HC (Heavy Combination) or MC (Multi Combination), it is strongly recommended that the applicant ensure they meet the medical requirements before commencing any training or tests for a heavy vehicle licence.