Montgomery County Council President Steven A. Silverman (D-At large) of Silver Spring said the entire council opposes building the so-called Techway over the Potomac.

"We're trying to get the ICC built," Silverman said. "Let's get that moving forward before we talk about building another bridge."

The Virginia study used infrared cameras to check traffic between five Maryland sites and 10 in Virginia between 6 a.m. and 9 a.m. last month, matching license plate numbers with ZIP codes.

The study, released Monday, found 30 percent of the cars on the Dulles corridor were Maryland vehicles; 38 percent of the traffic at the Virginia sites overall were from Maryland, and 54 percent of the traffic at the Maryland sites came from Virginia.

But Laura Olsen, assistant director of Coalition for Smarter Growth in Washington, D.C., pointed out that of the 12,796 Virginia cars identified at Maryland study sites, only 5,228 were identified as following the "horseshoe commute" from western Virginia to the I-270 corridor, and only 342 traveled all the way to Gaithersburg.

"Tyson's isn't western Virginia," she said. "If people are traveling from Bethesda to Tyson's building a bridge 40 miles out isn't going to do a thing for them."

Transportation Secretary Robert L. Flanagan said Maryland is still digesting the study. He said the state has no plans to embark on a Techway, but is considering widening the Capital Beltway with toll lanes that would extend into Virginia.

"There would seem to be good reason to connect up the toll lanes that Virginia plans and Maryland is studying," Flanagan said.

The Techway, which has been politically radioactive in Maryland, would slice through parts of Potomac or through Montgomery County's agricultural reserve.

"It's not going to happen," said Sen. Robert J. Garagiola (D-Dist. 15) of Germantown.

Garagiola said Montgomery should create more jobs on the I-270 corridor so Marylanders do not need to commute elsewhere.

Del. Jean B. Cryor (R-Dist. 15) of Potomac said there is "no money and very little political will to build a Techway."

Critics including environmental groups and the Coalition for Smarter Growth have called the Techway a sprawl-generating machine that would pave over communities and open space while harming air and water quality and sucking growth out of the area's urban core.

County Executive Douglas M. Duncan (D) will not support a Techway at the expense of existing communities and environmentally sensitive areas, said David S. Weaver, a Duncan spokesman.

Duncan favors a new crossing, Weaver said -- but only near U.S. Route 15, where a two-lane bridge already exists at Point of Rocks in neighboring Frederick County.

Meanwhile, business groups are calling for a link between the region's two burgeoning technology centers.

Robert O. Chase, president of the Northern Virginia Transportation Alliance, said the study did not go far enough to show the congestion that demands another bridge.

"The study reaffirms the need for an additional crossing but significantly underestimates the need because it only measured during a couple of hours in the whole day," he said.

Analysts should have tried to count the commuters who purposely delay their trip to avoid the commuter rush, he said. "They grossly underestimated where the rest of the demand is."

Robert T. Grow, government relations director for the Greater Washington Area Board of Trade, said the ICC has dominated transportation talk locally.

"There's only so much money out there, for one thing," Grow said. "If you're trying to get the ICC done, you have to focus on that and find where you can get the money. Once that's secured, you can think about other projects."

Momentum to address the Potomac crossing traffic has stalled for several years, ever since U.S. Rep. Frank R. Wolf (R-Va.) pulled the plug on a $2 million federal study at the behest of opponents in the community.

That study, Grow said, indicated dozens of potential crossings that together threatened to impact virtually every neighborhood in the area. "It made a lot of people nervous," he said. "Things have been quiet ever since."

Grow said he hopes the new study will propel officials toward settling on a single route that can be considered rationally by all sides.

"This may not even be a major bridge," he said. "Maybe it will be more like a Chain Bridge."

Grow acknowledged the arguments of anti-sprawl and environmental advocates but said there are ways to build a Techway to minimize the impact, such as making it a limited-access road or creating parkland buffers on either side of the bridge.

Staff Writer Margie Hyslop contributed to this report.