They are implying that people will drive to New Jersey and park then take the metro into NYC to avoid the toll vs just driving into NYC directly. You still would have to pay the bridge tolls or the tunnel tolls entering NYC so people who park and ride save both tolls now. You can get a month long metropass for pretty cheap too every time I am in NYC I always get a 7 day pass two if there for 7+ days. Too bad mayor Adams threw away all the good work Rudy did keeping crime down.
But how would that increase air pollution?