The Downtown area will likely suffer most, experts say, because an unusually high percentage of its workers depend on public transit. But thousands of businesses across the county could also be hurt because the Teamsters and other unions that belong to the 800,000-member AFL-CIO have pledged to honor picket lines, which means everything from the delivery of overnight packages to janitorial service at office buildings could be disrupted.

Some 6,800 bus and rail drivers, mechanics, clerks and others walked off their jobs Saturday morning after talks between their unions and the Metropolitan Transit Authority broke down. No new negotiations are scheduled, which means the strike could drag on for at least several days.

The typical bus driver earns more than $50,000 a year plus thousands of dollars more in overtime, the MTA says. Transit officials are asking the union to accept a four-day workweek to reduce overtime pay and also want changes in work rules that sometimes require highly paid mechanics to perform work that can be done by lower-paid employees.