OAKLAND -- A move-in delay at the future headquarters of the Bay Area's regional transportation agency will cost tollpayers an extra $5.4 million to temporarily house FasTrak, the agency's electronic toll-collection operation.

FasTrak was supposed to set up shop in the Metropolitan Transportation Commission's planned new office building at 375 Beale St. in San Francisco.

But the eight-story structure won't be ready to occupy until mid-2015, and the lease on FasTrak's current office expires this June, which leaves the operation's 146 employees and 1.4 million electronic accounts homeless.

To close the gap, the commission's Bay Area Toll Authority Oversight Committee on Wednesday reluctantly earmarked $5.4 million from its toll proceeds to move FasTrak into temporary offices for up to 18 months.

"It's not like we have a choice," said committee member and Berkeley Mayor Tom Bates. "(FasTrak) can't stay where they are, and we aren't ready to receive them. It was unfortunate timing."

The money will cover rent and building improvements for an interim FasTrak office at 62 First St. FasTrak allows motorists to carry an electronic device in their vehicles that automatically deducts tolls from a prepaid account.

The transportation commission initially planned to move into a fully renovated Beale Street building with three other regional agencies in 2014.

But the building's sole remaining tenant -- the federal Drug Enforcement Agency Western Laboratory -- apparently lacked the same sense of urgency. The agency occupies the top floor, and it isn't scheduled to move to new offices on Koll Center Parkway in Pleasanton until November.

The commission hired a contractor last summer and began renovations, but there is a great deal the construction team cannot finish until the building is empty, said commission spokesman Randy Rentschler.

"Getting the DEA to focus on finding a new location has been a challenge," Rentschler conceded. "The federal government did not move at the pace we would have preferred, and there is only so much work the contractor can do at night and on the weekends."

The commission's other challenge was finding FasTrak an interim home in San Francisco's hot real estate market.

The landlord at FasTrak's current offices on Embarcadero Street in San Francisco wouldn't extend the lease past June 30, and few were interested in a short-term lease.

The extra $5.4 million in costs is likely to fuel more criticism of the commission's controversial 2011 decision to buy the large $90 million former post office, share it with other agencies and rent out the unused space.

In addition, the initial $80 million renovation cost estimate has ballooned to $124 million.

Angry over what he considered an improper use of toll dollars, state Transportation Committee Chairman Mark DeSaulnier, D-Concord, unsuccessfully attempted to block the deal.

Contact Lisa Vorderbrueggen at 925-945-4773, lvorderbrueggen@bayareanewsgroup.com or Twitter.com/lvorderbrueggen.