The state’s 520 Tolling Implementation Committee held a July 29 open house in Bothell to discuss tolling scenarios that would help pay for a new floating bridge across Lake Washington.

Elected officials from the Northshore area were at the meeting to demand mitigation for any new traffic that hits Highway 522 and nearby arterials as a result of the final plan.

The fear is that tolling will prompt motorists to drive around the lake using alternate routes.

“In terms of quality of life, this is singularly one of the biggest issues we’re going to face,” said Bothell City Councilmember Tim Tobin, who attended the meeting. “We come crashing down when 522 gets backed up.”

King County Councilmember Bob Ferguson told the tolling committee: “The one issue I care about most from my constituents in Kenmore and Lake Forest Park is 522. If there is tolling on 520, I strongly believe there needs to be significant mitigation for impacts on 522.”

The state plans to spend up to $3.9 billion on the new 520 floating bridge, and has already secured around $2 billion for the project.

Legislators have indicated that they expect the remaining $1.5-$2 billion to come from motorists who use the structure.

A preliminary study from the state suggests that the fees could run up to $6.85 per round trip during peak hours, although rates would be variable throughout the day.

“It’s critical to replace the bridge, and tolls are part of the equation,” said Washington State Department of Transportation spokeswoman Janet Matkin.

There is doubt as to whether lawmakers from outside the Puget Sound would be willing to fork over more than $2 billion — roughly half the project cost — that they’ve already assigned to the new bridge.

“As a social policy, we’re talking about a very unfortunate situation right now,” Tobin said. “It’s unfortunate that we have to fund transportation in this way.

“The question is whether our legislators can put up a fight to minimize the tolling. The political leaders up here really need to start screaming and shouting.”

A new 520 bridge is expected to be in place by 2014, with additional enhancements to the corridor scheduled for completion by 2016.

The state is currently studying four tolling scenarios:

• Toll the existing 520 bridge starting in 2010

• Toll the 520 bridge in 2010, and the Interstate 90 bridge starting in 2016

• Toll the new 520 bridge in 2016

• Toll the 520 and I-90 bridges starting 2016

Early data from the state suggests that none of the plans would increase traffic along 522 by more than 900 motorists per day.

But political leaders in the Northshore area aren’t buying it.

Kenmore Mayor David Baker joined the mayors of Lake Forest Park and Woodinville in signing a letter that criticizes the state for using a 1999 traffic survey to come up with its figures. They noted that “better data on demand during peak hours will be critical to fully understand the impact (of tolling).”

The group also called for a list of mitigation measures, such as Bus Rapid Transit service along 522 and completion of all planned improvements along the road before tolling begins; more transit capacity along Interstate 405; and additional Park-and-Ride facilities in the Northshore area.

The tolling committee plans to hold six public meetings before Aug. 13, and will also conduct phone- and Web-based surveys this fall to gather additional input before submitting a report to the governor in January.

Part of the team’s goal will be to determine how accurate the state’s traffic models were, Matkin said.

• Visit www.build520.org for additional information from the 520 Tolling Implementation Committee.