My boich tells me that the East River crossings are likely less than 2000 amos. They are made for walking (at least the W-brg bridge and Bkln bridge are) and in the 20s-50s, people regularly walked between Williamsburg and the East Side.
The Verazzano Bridge is far longer than 2000 amos and was made primarily for vehicular traffic-not walkers. There may be more of a problem there.
(I know the shiur for burganys would be 70.7 amos, but that is chutz la’ir. When you’re in the city limits, we are not machmir on gaps that small.)