The two sides have been unable to reach a deal in talks prior to this week's strike, and the transit blamed the union for the halt in service in San Francisco.
"BART has received no indication that ATU and SEIU will return to work Wed., July 3rd.," the agency said in a statement. "Commuters should make alternative plans. We are sorry that the actions of ATU and SEIU have caused such a tremendous disruption to the people of the Bay Area. We are working hard to bring a fair and responsible resolution to labor talks."
The unions for the transit workers have offered a starkly different take on their decision to strike.
"We are deeply disappointed at the current situation with BART," the SEIU's Local 121 wrote on the website keepBARTrunning.com.
"We are proud of our jobs and work hard to get you where you need to go," the union's post continued. "Trust us when we say that we want to get back to work just as much as you want us to."
The union said their issues with the management of the BART system were not just about compensation for its members.
"We have tried for months to work with BART’s high-paid negotiators to address critical safety issues in the system," the union wrote. "Workers have died because of the current lighting situation, but BART refuses to address this issue at the bargaining table. We want to open bathrooms in stations and keep them clean and safe, but BART won’t address that either. We want to ensure that the system is fully staffed so we have the capacity to keep trains, tracks, and riders safe."
However, the union did acknowledge that "some of this is about fair pay.
"We gave up over $100 million in concessions in our last contract negotiations, and we haven’t had a raise in five years, yet the cost of living in the Bay Area has spiked by over 18 percent," the SEIU wrote. "Meanwhile ridership is at record high and the system is running at peak condition. We are being asked to do more, with fewer workers and less pay. Its not fair and it hurts our ability to serve the riding public."
Transportation observers are watching the impact of the strike on new car sharing services.
The San Francisco BART system normally trails New York City's subway, Washington, D.C.'s, MetroRail, Chicago's "L" and Boston's "T" subways in daily ridership among U.S. public transportation agencies.