BART has said union train operators and station agents average about $71,000 in base salary and $11,000 in overtime annually. The workers also pay a flat $92 monthly fee for health insurance.
Commuter Hilary Hartman, 26, said she has a hard time sympathizing with the unions' demands for more money.
"They make almost twice as much as I do," Hartman said while waiting on Tuesday to take a bus from San Francisco to her job in Berkeley. "I work for a nonprofit. If I don't do my job, I get fired. I'm kind of like, please come do your job so I can do my job."
Despite such feelings, no backlash is likely against the union, said Steven Pitts, a labor policy specialist at the University of California, Berkeley's Center for Labor Research and Education.
Even though only about 11 percent of workers in the nation are union members, California is one of the more heavily unionized states in the country, he said, with San Francisco and Los Angeles serving as union strongholds.
"In this case, BART's unions feel that they have some leverage due to the lack of similar transit alternatives in the area, and BART can't run the trains without its workers," Pitts said.
BART travels through the farthest reaches of San Francisco's densely populated eastern suburbs to San Francisco International Airport across the bay. With 44 stations in four counties and 104 miles of lines, the trains handle more than 40 percent of commuters coming from the East Bay to San Francisco, area transportation officials said.
To aid commuters, BART has extended the hours of carpool lanes and added ferries and buses.
The unions — which represent nearly 2,400 train operators, station agents, mechanics, maintenance workers and professional staff — want a 5 percent raise each year over the next three years.
BART said it is offering an 8 percent salary increase over the next four years as well as reducing the amount of employee contributions it originally requested for pension and medical benefits.