Any time you're operating a for-hire vehicle with a Gross Vehicle Weight Rating of over 26,000 lbs., or any time you're operating a vehicle of any weight class which is either hauling a quantity of hazardous materials which requires placarding, or is designed to transport more than 15 passengers (including the driver). That's federal law.
Yes. A CDL doesn't nullify the requirement for a motorcycle endorsement.
No, the procedure for switching states is the same with a CDL as it is with any other class of licence. If you have a Hazmat endorsement, however, and obtained it before the requirement for fingerprinting and a TSA background check went into effect, however, you will have to go through that if you wish to keep that endorsement.
The requirement for when a CDL is needed is not based on a vehicle's length.
You need that in EVERY state.
Either find employment with a company which will do your CDL training in-house, or go to a truck driving school. There are several private truck driving schools, and many community colleges have CDL driving courses.
It is a CDL restriction in all states and territories of the United States.
No, there is no such requirement for commercial vehicles in any state.
Any vehicle with a semi trailer is going to require a Class A CDL. Classes B and C are for large passenger vehicles and towing vehicles.
There is no requirement for CDL refresher training however there are Supervisor refresher courses available (like the FAA's), for less than $25 dollars online.
Yes, so long as you meet the age requirement.
Yes. It's a federal requirement applicable to all states.
There is a license requirement to drive a pumper truck in Florida. The requirement is a class B CDL license.