PETALUMA -- Petaluma will soon serve as the new headquarters for the Sonoma Marin Area Rail Transit District, with a new location consolidating the two current offices in Santa Rosa and San Rafael and providing room to grow for the commuter rail agency.

SMART’s board of directors voted Wednesday to authorize a six-year lease with San Mateo-based Cornerstone Properties of 25,000 square feet on the top floor of an office building at 5401 Old Redwood Hwy., at a cost of $1.70 per square foot with a 3 percent annual escalation. Total rental cost per year would be approximately $510,000.

The new property will be able to house more than 100 workers, including consultants and a SMART staff expected to grow past 75 employees. The rail agency currently is based at 750 Lindaro St., Ste. 200, in San Rafael Corporate Center and has a project office at 490 Mendocino Ave., Ste. 102, in Santa Rosa.

A SMART committee looked at 12 area properties during the search, according to the board. The final lease was among three finalists, which real estate sources said included a downtown property owned by Basin Street Properties and a property at 1039 N. McDowell Blvd. owned by PB&J Acquisitions and Investcorp International.

Shirlee Zane, a county of Sonoma supervisor and agency board member, lauded the decision but noted that the property would be five miles from the nearest station in SMART’s initial operating segment. Ms. Zane asked that staff consider providing a shuttle for workers.

“We have to set a good role model,” she said.