A constellation of Maryland business groups believe the state must raise more money for transportation, but they also want a constitutional amendment to wall off the funds so it can't be used elsewhere in the budget.

Members of the group, called START (State Transportation Alliance to Restore Trust), say they've become frustrated by Gov. Martin O'Malley's habit of closing budget shortfalls by raiding transit funds. In next year's budget, for example, O'Malley proposed taking $30 million from the Transportation Trust Fund to fill up the state's Rainy Day Fund.

Don Fry, the head of the Greater Baltimore Committee, said Tuesday that the repeated raids have caused "an undermining" of the Transportation Trust Fund. Kathy Snyder, the president and CEO of the Maryland Chamber of Commerce said "hundreds of millions of dollars" are needed to attack a backlog of transportation projects, but her members are hesitant to support new revenues -- like a hike to the gas tax -- out of fear that the funds would be moved elsewhere.

A tax package aimed at replenishing the trust fund will be introduced in coming days by Senate Majority Leader Rob Garagiola, who also supports protecting the money for transit projects. He estimates the state needs an additional $400 to $600 million a year, but wouldn't provide details about his plan on Tuesday. One option frequently discussed is an increase to the gas tax: One penny nets the state $30 million.

But Garagiola has a timing problem if he wants an ironclad protection on money he'd raise this year. Changes to the state's constitution must be approved by the voters and they won't see another ballot until November 2012.