The International Drivers Permit or IDP is simply a booklet with translations in various language of your own driver license. It always needs to be shown together with your original drivers license.
If it is connected with your own license, why does an IDP always have a very limited validity (1 year)? Wouldn't it be logical to use the same validity as your own license? The terms in your license don't change, so why need a new translation document every year?
The one year validity was originally set in the 1949 Geneva Convention on Road Traffic and agreed upon. Anyway, in the 1968 convention of the same topic it was changed to no more than 3 years validity after the date of issue or until the date of expiry of the domestic driver's license, whichever is earlier, but it seems that this is not followed.
From Wikipedia
According to the 1949 Convention on Road Traffic, an IDP remains valid for one year from the date of issue. However, according to the Vienna Convention, an IDP remains valid for no more than three years from the date of issue, or until the expiration date of national driving permit, whichever is earlier. An IDP is not valid for driving in the country where it was issued.
