你NJ州的規定:
If you have recently moved to New Jersey, you must transfer your out-of-state license within 60 days of your move or before your current license expires, whichever occurs first.
http://www.state.nj.us/mvc/Licenses/Replacing.htm
後果:
If you are driving without a valid license in New Jersey, you may be charged with driving without a license. This offense can result in hefty fines and court costs, plus the New Jersey Motor Vehicle Commission can refuse to issue you a license for 6 months after the date of the conviction. If you become involved in an auto accident while driving without a valid license there are also additional penalties, including possible jail sentence. There are also surcharges you may be assessed by the Motor Vehicle Commission.