I've twice bothered to get an international drivers license in the US for
periods living abroad. Each time I went to the AAA (Automobile Association)
do so, and it was essentially a certified para-document to be used alongside
my US drivers license restating the relevant information. As I recall, box 1
was my full legal name, box 2 was my date of birth, box 3 was the official
license number of my US state license, box 4 and 5 issue and expiry date,
The rest of the passport size document was text to the effect that box 1 was
my full legal name, box 2 was my date of birth, box 3 was the official
number of my US state license, box 4 and 5 issue and expiry date, etc., but
about 9 languages.
I can see that it would be useful even when not required, if the official who
needed your documentation did not read American.
Only problem I've ever had without one is with a UK car-hire company who
only consider my US state driver's license as equivalent to a UK "automatic
only" license. They wanted me to pay the rate for an Omega (the automatic
vehicle they had available) when I had reserved a Corsa.
Douglas ('70 BGT)
Edit your replies