Ash,
Just so that you know. An 'international drivers license' is nothing more than an extension to your regular drivers license. What makes an international license different is that it explains in the foreign language that you are visiting all that your present license says in your native language. If you should have one in your possession when stopped it would make the police better able to read what restrictions you may have as it will be in their language.
Upon investigation with the Division of Drivers Licenses here and AMET the DR does not issue an international license for anyone wishing to acquire same. A little strange in my opinion as it would make it so much easier for those Dominicans traveling to other countries.
Per the Ley 241, Transito de Vehiculos, page 57, T?tulo III, Cap?tulo I, Art. 20 - Personas exentas del requisito de licencia. says;
"a. Toda persona que est? debidamente autorizada para conducir un veh?culo
de motor en cualquier pa?s extranjero donde se exijan requisitos similares a
los establecidos por esta Ley para la concesi?n de licencias de conductor, y
que posea y lleve consigo una licencia autorizada y en vigor en dicho pa?s
extranjero, estar? autorizada para conducir tal tipo de veh?culos de motor en
la Rep?blica Dominicana, durante los primeros noventa (90) d?as desde su
arribo."
http://www.amet.gov.do/LEY241/LEY241.pdf
Of course whether an AMET official wishes to argue this with you is another mater.
Hope this helps.
Rick