San Francisco's Bay Area Rapid Transit (BART) announced Monday morning that two of its unions are on strike following an inability to agree on new contracts, shutting down the transit system and disrupting more than 400,000 riders who use the nation's fifth-largest rail system for their daily commute.

The transit system announced on its website that "there is no BART service on Monday" and that "transit riders and drivers need to plan ahead for their commutes" and "consider alternative transportation."

"Employers are encouraged to allow their employees to telecommute," the statement writes.

AC Transit's strike has been averted for now and is running normally.

The BART Twitter page urges San Francisco drivers to "form a carpool now" and to "find...pickup locations."

The BART strike comes after talks with its two biggest unions, Service Employees International Union Local 1021 and Amalgamated Transit Union Local 1555, came to an end after management failed to produce a contract before the midnight deadline on Sunday.

"If there are no new proposals by midnight, then workers will walk off the job as soon as the trains are safely put to bed," Josie Mooney, a negotiator for the SEIU, told the Associated Press.

The International Business Times reports that BART and the unions were far from figuring out key issues including salary, pensions, health care and safety, and the two unions walked away from the negotiating table last night.

The two unions, which represent nearly 2,400 people, want a 5 percent raise each year over the next three years. 

The BART website warns that during the strike, many employees will try to drive to work instead of taking public transportation. Because of this, "thousands of additional drivers will likely be on the road."

The website recommends that to get to work, San Franciscans should: "telecommute or avoid traveling altogether, form a carpool or try casual carpooling, take advantage of free parking at any BART station or Park & Ride lot to meet your carpool, adjust your work hours (leave early or stay late), ride your bike, allow extra time for your trip."

Due to the increased number of drivers on Monday, BART advises East Bay drivers to "expect significant delays on the Richmond San Rafael Bridge." 

Transportation officials say another 60,000 vehicles could be on the road, clogging highways and bridges throughout the Bay Area, the International Business Times reports.