Festival-goers are encouraged to leave their cars at home and take public transportation. But if you must drive, it is better to park in a public lot (of course check with attendants for costs and hours of operation) or street parking. Holiday parking rules will be in effect on July 4, but will resume to normal regulations on Wednesday, July 5.
From NYC via Holland Tunnel
From North/South Jersey
Take the New Jersey Turnpike to exit 14B toward Jersey City.