It is not so different in NJ and PA. No vehicle may be legally registered (valid license plates) or operated on public roads without minimum insurance coverage. The insurance is on the car, not the driver (though the car owner's driving record, and any household members with driving licenses when calculating the premium).

However, anyone driving the car is also responsible for ensuring the vehicle is insured. So if you are driving a friend's car and he hasn't paid his premium, you can get ticketed, fined and suspended for operating someone else's car without insurance. This happened to a friend of mine several years ago. His uncle loaned my friend his van to pick-up a sofa. My friend was pulled-over for having a light out and the officer discovered his uncle's insurance had expired. He paid over $1,000 in fines and surcharges and lost his license for six months.

And the same thing happens in the US regarding certain cases of illegal operation, such as driving while drunk or with a suspended license. The insurance company will pay off the other damaged persons but then go after the insured and/or driver for whatever damages were paid out. For example, say your son's license was suspended and he drove your car and had an accident, and your insurance policy excludes coverage for persons driving without a valid license. Your insurance company would pay the other car owner's damages and then bill you and your son for what was paid. If you didn't pay they would get a judgment against you in court and have your driver's license suspended until you did pay.