Is it a "driver license" or a "driver's license" or a "drivers license" or...what?

I've often wondered why my Ohio license is called a "driver license". It is awkward to say it like that.

Wouldn't something like driver's license be more appropriate?

Or driving license (like hunting license)?

(Note: image above shows driver, driver's, and drivers variations.)

New Oxford American has this:

driver's license |ˈdraɪvərz ˈˈlaɪsns| noun a document permitting a person to drive a motor vehicle. driving licence noun British term for driver's license .

Actually, try reading it like this:

Licence of Driver.

I don't think there's anything wrong with it, although we would be more comfortable saying "driver's" or "driving"

"Driver" is just describing what kind of a license it is, not whose. Other examples would be "bar-tender license" not "bar-tender's license"

The answer is that the name of the document is prescribed by law. The name is just whatever was chosen when the legislation was written.