Translate. IDPs ensure that your domestic driving license is understandable by local authorities and officials in the foreign country where you are driving.
Certify. The issuer of your IDP certifies that you have a valid driving license in your country of residence, i.e. that you are authorized to drive motor vehicles.
Type of vehicle. The issuer of your IDP also indicates and certifies what category or categories of motor vehicles you are authorized to drive.
Improve Road Safety. The fact that IDPs are often required to drive abroad helps ensure that every driver is an authorized driver, and helps improve road safety worldwide.