New York - A travel ban was slapped on Saturday on New York and its suburbs, with authorities shutting roads and cancelling rail service as a massive snow storm pummelling the US East Coast took aim at the Big Apple.Road travel in the so-called downstate area of New York, Long Island and the lower Hudson valley was to begin at 14:30 (19:30 GMT), state Governor Andrew Cuomo announced.Commuter trains connecting the suburbs to Manhattan were to be suspended from 16:00, along with above-ground subway service. Bus service in New York has also been cut off."Public safety is job 1," Cuomo said on Twitter."This will very likely be one of the worst storms in City history. Go home. Stay home. Stay safe today," New York Mayor Bill de Blasio tweeted.Public transit in Washington was shut down for the weekend, as was most rail service in Philadelphia as the monster storm - dubbed "Snowzilla" - dumped mounds of snow along the US East Coast. Up to 60cm was expected in major cities.