It applies only to Commercial Driver Licenses (CDLs). "U" is the code for "intrastate only" (as it pertains to operation of a Commercial Motor Vehicle). It's given to people who either get a CDL when they are below the age of 21 or who self-certify themselves as "intrastate exempt" or "intrastate non-exempt" drivers.
Restriction codes vary by state. You would need to specify the state you are referring to.
Varies by state. Usually, a regular license, but which has a restriction of some form on it.
If your drivers license is revoked in one state, can you get a drivers license in another state?
18 and already holding a valid Ohio drivers license. If you get a CDL before you're 21, you'll get an "intrastate only" restriction which prohibits you from operating a CMV outside of your home state, and you will not be able to get a hazmat endorsemen.
No
No you cannot get a drivers license in Florida if you have had your license suspended in another state.
No
No. Federal states that if you have a CDL in one state, you cannot have any other drivers license in any other state.
No. Not until your license is reinstated in your state. No state will give you a license until you clear that up.
No
None
Short answer, none.