Some of the roadways (especially near terminals) are restricted: no cars, only busses; making mass transit (essentially) the only option for direct access.
But in true PANY-NJ style, they just start building without taking into account how it would effect traffic.
Is the upper (departures) or lower (arrivals) roadway at Central Terminal B closed to private cars?
That would be absurd. The parking lot there has been closed, and there is no rail connection. Say it ain't so.