Visitors with a foreign driver license who travel to the United States should carry an IDP or attach an acceptable English translation to their national driver licenses. The IDP is translated into the official languages of the United Nations (including English) and is useful in traffic emergencies. Non-citizens must obtain the IDP in their native country before traveling to the United States.
http://www.state.nj.us/mvc/pdf/Licenses/Driver%20Manual/Chapter_1.pdf
Visitors with a foreign driver license who travel to the United States should carry
an IDP or attach an acceptable English translation to their national driver licenses.
The IDP is translated into the official languages of the United Nations (including
English) and is useful in traffic emergencies. Non-citizens must obtain the IDP in
their native country before traveling to the United States.