CITY HALL — The City Council on Tuesday put off a decision on increasing Big Blue Bus fares at least until its next meeting on May 11, a move a spokeswoman for the bus system said could make it more difficult for transportation officials to implement a potential fare increase by their Aug. 29 target date.

BBB officials said they need a substantial fare hike to help offset reduced transportation funding from the state government and from local sales taxes.

Facing a projected $6.1 million deficit, they’re aiming to earn an additional $2.6 million from higher fares during the next fiscal year, which begins July 1.

In delaying their decision, several council members said they understood the bus system needs additional revenue but said they didn’t have enough information to decide how much to increase fares.

The council directed BBB officials to submit an analysis of the impacts of potential service reductions before the next meeting. Members also asked for more information about possible new revenue streams and about the effect increasing the general fund’s subsidy to the BBB would have on other City Hall programs.

Several members also said they were concerned the proposed increases would burden seniors, the disabled and students and would result in too great a decrease in ridership.

The most moderate proposal before the council on Tuesday was to hike the regular fare from 75 cents to $1.25, increase the student fare from 50 cents to $1.25, and increase the fare for seniors, the disabled and those on Medicare from 25 cents to 60 cents. Discounted transfers between BBB lines would also have been eliminated under the plan, a step officials said was meant to encourage riders to buy all-day and monthly passes, which offer discounted fares and make boarding more efficient.

Stephanie Nergriff, the BBB’s director, said she expected ridership to decrease by 17 percent, or 3 million riders, as a result of the proposed increases. Ridership decreased 12 percent after a fare increase in 2002, and while the number of riders has steadily increased since then, fewer people used the bus in 2009 than in 2002.

City Manager Rod Gould made it clear the council will have to approve a fare increase or else be prepared to accept reductions in service that could impact low income people who rely on the bus system to get to work.

Without an increase, City Hall projects the BBB’s deficit would grow to $16 million by 2015.

Linda Gamberg, a spokeswoman for the BBB, on Wednesday said if the council approves a fare increase on May 11 the bus system believes it will be able to re-program bus fare collection boxes and make other preparations to implement the increase on Aug. 29, the date of the bus system’s fall reorganization. If the council further delays a decision, she said, any potential increase would have to be postponed until winter and would exacerbate the projected deficit.

“For this coming fiscal year, if we don’t hit that Aug. 29th mark, then we’re losing approximately $8,500 per day” compared with revenues a fare hike would bring in, she said.

“As much as we’d like everyone to always be able to ride for free, unfortunately that’s not the climate we’re living in right now,” Gamberg said.

nickt@smdp.com