By Andrew Chamings : sfgate – excerpt

The long-planned express lane on a 22-mile stretch of Highway 101 on the San Francisco Peninsula is now open for business. Tasked with reducing traffic on one of the gnarliest commute stretches in the Bay Area, the lane rewards carpoolers — but comes at a cost to others.

Here’s a breakdown of how the new 101 express lanes work: They’re now open between I-380 in South San Francisco and Whipple Avenue in Redwood City. Use of the lane is free for vehicles with three or more people, two-seat cars with two people, buses and motorcycles. For the rest, the pricing gets a little more complicated.

The cost to enter the express lane is constantly changing, depending on traffic. That one-time charge — anywhere from 50 cents to $12 — will be displayed on electronic signage above the lane. Motorists traveling solo with a FasTrak tag can choose to take that price and enter the lane. The charge will be applied to their bill…(more)