Marin County is narrowing in on trends behind recent traffic buildups on the county's highways and bridges, contemplating ways that current, future and potential projects may ease congestion and smooth commutes.

[caption id="attachment_89580" align="alignleft" width="320"] Gary Phillips[/caption]

The issue is one of central economic importance to the North Bay, where San Rafael Mayor Gary Phillips recalled the challenge of opening a branch for his San Francisco-based architecture firm in San Rafael.

"Hiring was extremely difficult, transportation being what it is," said Mr. Phillips, addressing a room of business leaders gathered March 13 for the North Bay Business Journal's annual Impact Marin conference.Hwy. 101 traffic study

Helping to drive that enhanced understanding of regional traffic patterns are the results of a recent car-tracking study by the Transportation Authority of Marin. It reveals in detail the direction of Highway 101 traffic as it crosses the Golden Gate Bridge during peak commute hours.

The study found 10 percent of that northbound traffic to be continuing toward the Richmond--San Rafael bridge, a larger-than-expected percentage. Forty-one percent exited at Ross Valley or San Rafael and 26 percent at San Pedro and Highway 37. Twenty-four percent continued on the freeway north of Highway 37.Third bridge lane

The numbers support a recent sense for many commuters that traffic involving the Richmond--San Rafael Bridge has contributed to a growing snarl in central and southern Marin, according to conference panelists. That is prompting talk of repurposing the current eastbound shoulder of the bridge as a third lane and long-term talk of reducing a bottleneck at Highway 580's merge with Highway 101.

"This is great in terms of adding jobs," said Dianne Steinhauser, executive director of TAM, of the higher number of commuters. "With that growth comes more traffic."

TAM has requested $2.3 million in funding from the Bay Area Toll Authority to study the bridge lane-conversion proposal. If approved, third lanes on the bridge could open as early as the middle of 2016.Million on SMART annually

[caption id="attachment_70937" align="alignleft" width="200"] Farhad Mansourian[/caption]

Other efforts that may alleviate commute traffic include the Sonoma Marin Area Rail Transit system, which expects to begin operation in 2016 and ultimately transport 1 million passengers per year, said Farhad Mansourian, general manager and another conference panelist.

Mr. Mansourian noted recent efforts to identify funding that would extend the initial operating stretch of the system from downtown San Rafael to the Larkspur Ferry Terminal. That would significantly expand the system's ability to connect with the rest of the Bay Area and help attract workers to Marin County, he said.

"If we can get to Larkspur, we're connecting a regional ferry and a regional airport," he said, noting recent success in adding a planned station near Charles M. Schulz--Sonoma County Airport north of Santa Rosa.

Mr. Mansourian stressed SMART's potential to boost the mobility of tourists, and that business owners could stand to benefit by serving travelers throughout the corridor.'Narrows' gap narrows

While exploring possibilities to ease congestion on the Richmond--San Rafael Bridge, Ms. Steinhauser acknowledged that expansion of Highway 101 to add a third lane each way in the "narrows" between Novato and Petaluma remained $250 million short in funding.

"I call it the bastard stepchild between Marin and Sonoma County," she said. "Throughout the Bay Area, we have all these linkage routes that nobody wants to own."

Meanwhile, the broader Highway 101 improvement effort has advanced. Construction to extend a northbound high-occupancy vehicle lane past Olompali State Park north of Novato and a southbound lane starting at Delong Avenue in Novato is expected to be completed this summer.

Construction of a rebuilt Redwood Landfill interchange and elimination of frontage road access in the narrows is also expected for completion at that time.

Ms. Steinhauser expressed confidence that further funding will eventually be identified.

"It is a key economic corridor, and the state is committed to funding it in the future," she said.