We could end up with youngsters paying full fare on the trains because motorists were spared paying a toll to cross the same span. The observant kids will note that most of the motor vehicles are private cars occupied by one person. PERHAPS THE KIDS will be able to take some comfort in sailing past motorists sitting in bumper-to-bumper traffic, as the motorists were as I rode the J train over the Williamsburg Bridge yesterday. I got off at the first stop in Manhattan. I reached the street in plenty of time to watch cars I had seen stuck on the bridge roll into Shelly World toll free, spewing pollution and doing their bit to keep us dependent on foreign oil.