NEW YORK, Dec 20: The New York city subways and buses came to a grinding halt early on Tuesday morning as over 33,000 transit workers walked off their jobs at the peak of holiday shopping and tourist season forcing some seven million people to find alternative ways to get to work.

New York city Mayor Michael Bloomberg said the strike would cost the city as much as $400 million a day.

City authorities began locking turnstiles and shuttering subway entrances shortly after the Transport Workers Union ordered the strike.

Streets were crowded with workers bundled up against the bitter cold. Cars were backed up at arteries leading onto the bridges, tunnels and major expressways that feed into Manhattan, as the police peered into cars to enforce the four-passenger rule, turning some away and letting others pass.

At one subway booth, a handwritten sign read, ‘Strike in Effect. Station Closed. Happy Holidays!!!!’ At Penn Station, an announcement over the loudspeaker told people to ‘please exit the subway system’.

Mayor Bloomberg said that the strike would be particularly harsh taking place during the holidays. He said a strike would freeze traffic into ‘gridlock that will tie the record for all gridlocks’.

He began putting into effect a sweeping emergency plan to reduce gridlock and keep certain streets open for emergency vehicles. It included requiring cars coming into Manhattan below 96th Street to have at least four occupants.

New Yorkers were urged to make arrangements to carpool, bicycle and walk to work, or change their schedules and work from home.

The union called the strike after a late round of negotiations broke down Monday night. Union President Roger Toussaint said the union board voted overwhelmingly to call the strike.

“This is a fight over dignity and respect on the job, a concept that is very alien to the MTA,” Toussaint said in announcing the strike.

“Transit workers are tired of being under appreciated and disrespected.”

The news drew an angry response from the mayor, governor and head of the Metropolitan Transportation Authority.