For the hefty price of $340 million, Sonoma County could one day have an unrivaled bike path system, though transportation planners concede that the hard reality of tight funding could put that goal a long way down the road.

The entire 1,060-mile proposed bike network would cost about as much as adding 12 miles of carpool lanes to Highway 101 through the Sonoma-Marin Narrows. If the whole network were ever built, it would quadruple the number of bike-path and bike-lane miles in Sonoma County, making it one of the most cycling-friendly places in the nation.

But transportation officials have identified only a tiny fraction of the needed funding and acknowledge that there is little chance the whole network will be completed anytime soon.

Instead, they say, making a wish list that includes each segment in the proposed network -#8212; there are 977 segments countywide -#8212; helps secure funding when the opportunity arises.

"Bike projects are different than other projects," said Janet Spilman, deputy director of the Sonoma County Transportation Authority. "They are largely opportunistic. It's a good idea to keep the list fresh."

The transportation authority is updating the countywide bike plan for the first time since 2008. Back then, the county had 241 miles of bike infrastructure, mostly in the form of on-street bike lanes.

The update comes as cycling has boomed in Sonoma County, with triple-digit growth and an increasing array of recreational and competitive events such as the popular Levi's GranFondo and the Tour of California.

In the past six years, the county and its cities have built a total of 73 miles of bike lanes and paved bike paths, according to the updated Countywide Bicycle and Pedestrian Master Plan. The blueprint combines the independent plans of the county and its nine cities.

"It's a guiding document for each one of our jurisdictions," said Eydie Tacata, vice chair of the Countywide Bicycle and Pedestrian Advisory Committee. "We want to make sure all the plans connect."

The committee met Tuesday to finalize the plan and could approve it at its next meeting in March. The transportation authority could adopt the plan in May.

County officials tout specific bike path projects that have benefited from inclusion in the plan. In 2009, the county was able to pave the final 2.1-mile section of the Santa Rosa Creek Trail using state and federal money. The project may not have received funding if it wasn't on the master list, transportation officials said.

"Without having a project identified in a planning document, the county cannot proceed with a project," said Ken Tam, a park planner with Sonoma County Regional Parks. "In order to qualify for state and federal funding, it's got to be in a document."

But inclusion on the list doesn't guarantee that a segment of path will receive funding, officials say, and many high-priority bike paths identified in the previous bike plan remain unfunded.

Some segments of pathway that are carried over from the previous plan include a 12-mile bike path from Santa Rosa through the Sonoma Valley that planners estimate would cost $5 million; an 11-mile path from Petaluma to Sebastopol with a $4 million price tag; and 11 miles of paved Petaluma Marsh Trail at a cost of $4 million. The plan also lists smaller projects, including a proposal for bike-route signs on one block of Third Street in Cloverdale, at a total cost of $967.

"Everything is thrown in there to make sure that when there's money we can grab a project off the list," said Gary Helfrich, executive director of the Sonoma County Bicycle Coalition. "The odds are zero that they will all get built."

There are a number of reasons to improve the county bicycle infrastructure, transportation planners say. Giving commuters another option to get to work takes a car off the road, helps ease traffic and improves air quality. Bicycling has increased by 104 percent in Sonoma County since 2010, according to the Metropolitan Transportation Commission.

Separate lanes and pathways helps keep cyclists safely away from traffic, planners say. Since 2008, there were 1,450 traffic collisions in Sonoma County involving a cyclist or a pedestrian, according to the CHP.

Transportation planners say there is not an imminent funding source for any of the bike projects, but cities and the county will use the plan to seek federal, state and regional money in the near future.

"It's really a great tool for our jurisdictions to use to find funding for specific projects," said Diane Dohm, transportation planner with the SCTA. "It's definitely an active plan. It doesn't just sit on a shelf."

(You can reach Staff Writer Matt Brown at 521-5206 or matt.brown@pressdemocrat.com.)