Here is your New Jersey law regarding go karts..........
A go-cart is not "street legal" to run any motorized vehicle on the street it must at minimum have turn signals, mirrors, break lights, registration, head lights, tail lights and be insured and you need to be licensed.
The fine for using a go-cart on public roads, sidewalks and so forth is a minimum of $250.00 and not more than $500.00.