On the heels of a recommendation to build a rapid-bus line to serve the upcounty, business leaders and mass transit advocates are rallying behind the light rail option for the Corridor Cities Transitway, which would run from the Shady Grove Metro station west to Gaithersburg then north through Germantown to Clarksburg.

Montgomery County planners recommended last week that the state choose the rapid-bus option for the CCT, based largely on ridership projections. The bus option also "increases flexibility" in building the CCT in segments and in pursuing financing, according to the staff report.

In recent discussions of the Gaithersburg West and Germantown master plans, Planning Board members have expressed support for the bus option as more efficient than light rail, and therefore more likely to qualify for a federal program that typically covers up to half of a mass transit project's cost. According to state projections, the bus option would cost $449 million, while light rail would cost $777 million.

Rapid bus would carry 21,000 to 27,000 riders and take 38 minutes, according to state officials. Light rail would carry between 24,000 and 30,000 riders daily and take 36 minutes from Shady Grove to Clarksburg.

The Planning Board is expected to issue its recommendation Monday night after a public hearing. That will then go to the County Council for the county's official preference. The council is scheduled to begin its deliberations July 13.

The state decision on mode and alignment is expected this fall.

Groups including the Gaithersburg-Germantown Chamber of Commerce, Action Committee for Transit, Johns Hopkins University and the CCT Coalition are calling a recommendation for rapid bus premature. Ridership projections will change once the master plans for Gaithersburg West and Germantown are finished, they say, and the Federal Transit Administration may modify its funding criteria.

Light rail is a better catalyst for transit-oriented development and is seen as more permanent than rapid bus, said Richard N. Parsons, CCT Coalition member and past president and CEO of the county's chamber of commerce.

"Perceptions are important to investors, perceptions are important for ridership, too," he said.

As the CCT heads west toward Great Seneca Highway, planners recommended shifting the route south through the Shady Grove Life Sciences Center, which is envisioned to triple in development over the next 40 years into a live-work hub of biotech.

The realignment would shift a stop at DANAC Corp east to Diamondback Drive and eliminate the Decoverly stop. The new stations would be at Broschart and Blackwell, next to Shady Grove Adventist Hospital; the site of the county's police and fire/rescue training academy on Great Seneca Highway, which is envisioned as a 2,000-residence community; and at the Belward Farm on Route 28 and Muddy Branch Road, which Johns Hopkins University plans to turn into a biotech and applied sciences campus.

Shifting the alignment in the Life Sciences Center is expected to add about six minutes to the ride. The realignment through the Life Sciences Center would require a new environmental analysis by the state that would take a year or longer, pushing the CCT timeline back from its expected 2017 construction date, said Tom Autrey, a supervisor in the planning board's transportation planning department.

In the meantime, the planning board could recommend say light rail while keeping the bus option as a backup, said state Sen. Robert J. Garagiola.

"You see economic development around rail stations; I've never seen economic development around a rapid bus station," said Garagiola (D-Dist. 15) of Germantown.