A spokeswoman for the project, Amy Danberg, says the tolling would likely have variable rates, like the toll lanes already in use on Highway 167 in south King County.
She says another option under consideration would increase the required number of people in a carpool vehicle from two to three.
The 40-mile Eastside Corridor of Highway 167 and Interstate 405 is the north-south freeway option to Interstate 5 through the Seattle area.
The Transportation Department has been working for more than a decade on ways to reduce congestion. Express toll lanes between Bellevue and Lynnwood are under construction and will open in 2015.
The transportation advisory group, made up of 30 members, also will advise the state Department of Transportation and Legislature on carpool exemptions, hours of operation, project timing, and funding for express toll lanes along the full 40-mile corridor. A plan will be delivered to the governor and Legislature by June 2013.
Express toll lanes give solo drivers the option to use carpool lanes by paying an electronic toll. Similar to Highway 167, the express toll lanes on I-405 will operate as an expressway within a freeway while allowing toll-free trips for transit and vanpools.
The advisory group will have three more meetings in the coming weeks to gather input on the plan.
More information: www.wsdot.wa.gov/tolling/eastsidecorridor