別打小算盤，在規定的時期內不更換新駕照，一旦被警察逮住，吃不了兜著走。

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.

https://teperlaw.wordpress.com/2011/04/27/driving-in-new-jersey-with-an-out-of-state-driving-license/