Brown expressed confidence that the governor and the Assembly's presiding officers would come together around a common plan. But he also conveyed the administration's misgivings about Miller's proposal to move away from Maryland's current funding model, in which residents of all jurisdictions pay the same taxes and fees for transportation.
Even without new revenue, Dormsjo said, some areas will be protected: bridge replacement, safety-related improvements and Baltimore-Washington International Thurgood Marshall Airport.
But he said that for the past two years, the State Highway Administration has for the first time fallen short of its target for repairing road surfaces. Meanwhile, he said, the Maryland Transit Administration could be looking at cutting back bus runs within the year.
As an example of the type of cuts that would have to be considered, Dormsjo mentioned the possibility of ending MARC train service between Baltimore and Perryville to save $5 million annually. Dredging of the port also would be affected, he said.
Perhaps the most consequential result of a failure to find additional revenue would be the shutdown of planning and engineering on the Red Line and Purple Line, which together carry a price tag of about $5 billion.
Henry Kay, the MTA's deputy director for planning, said that if the money runs out, the work that has been done so far — involving about 500 people and $120 million since 2000 on the Red Line alone — will be put into archives in the hope that the projects can someday be revived.
Fry warned the projects could lose their place in line for federal funding.
"You may be delaying these projects for as much as a decade if you're not ready to move forward," he said.
Not everybody thinks that would be a bad thing. Senate Minority Leader E. J. Pipkin, an Eastern Shore Republican, said the state already spends too much on mass transit. "Roads are getting squeezed out across the state," he said.
House Republicans held a news conference Tuesday at which they argued that instead of raising taxes on gas, the state should shift spending from transit to roads, raise bus and rail fares and shift money from the state's general fund to make up for the diversion of local highway funds in past years.
Aides to Miller, Busch and O'Malley say the three leaders' chiefs of staff are holding discussions. A spokeswoman for Busch said there may be new developments by late this week. While Miller keeps stressing that it's getting late in the session, others suggest there's still time to pass a bill once a consensus is reached.
"Everybody knows the needs," Busch said. "There seems to be a will to get it done."
This session is widely seen as the time to do it. Few expect senators and delegates to approve a revenue increase in 2014 — when they are up for re-election.
Baltimore Sun reporter Erin Cox contributed to this article.