A couple of years ago, before CDL was federalized, getting a CDL was pretty easy, perhaps as easy as doc described it. A friend of mine owns an ice company and a number of his employees had received their CDLs before the rules changed and I recall him trying to rush a few employees through before the regs changed. Those that didn't make it, and had to go through the process Wolbert mentions, got raises plus they were allowed to use one of the ice company's trucks to take the test.
The Congress of the United States enacted The Commercial Motor Vehicle Safety Act of 1986 (CMVSA/86) which requires that all of the individual states conduct uniform testing and licensing standards for all commercial drivers. It also established uniform standards for qualification, suspensions, and revocation. It requires that no commercial vehicle operator may possess more than one license. That license MUST BE ISSUED FROM THE DRIVER'S STATE OF LEGAL RESIDENCE.
Here are the CDL requirments for Iowa (one of the first one I could find on the Internet)
A Commercial Drivers License (CDL) is Required if you drive ANY of the following commercial vehicles for hire ANY place in the United States...
A vehicle with a manufacturer's gross vehicle weight rating (GVWR) of more than 26,000 lbs.
A trailer with a manufacturer's GVWR of more than 10,000 lbs. when the GCWR exceeds 26,000 lbs.
A vehicle designed to carry 15 or more passengers (excluding the driver).
A vehicle of ANY size or type which requires hazardous materials placards.
To Be Eligible For A Commercial Drivers License (CDL) you must ...
Take and pass the mandatory Iowa CDL license examinations that apply to you.
Be 21 years old (18 years old if ALL of your driving is within Iowa and you do not transport hazardous materials or drive double or triple trailer rigs).
Possess a valid medical certificate in accordance with MCSR regs. 49 CFR 391.41 - 391.49.
Certify that you do not hold a driver license from more than one state and certify that your driver license is not currently suspended, revoked, or canceled in ANY state, nor subject to any of these actions.
Surrender your current driver license.
Provide proof of your identification.
Pay testing and licensing fees.