i202 Fall 2010 School of Information, UC Berkeley

A new 14-miles long 680 express lane will be unveiled next Monday.  Tolls will be collected electronically from FasTrak transponders by overall antennas.  Furthermore, the toll will vary from 30 cents to six dollars based on the traffic flow of the non-toll lanes.  Therefore, the FasTrak center will be combining information collected from the Sigalert traffic and the transponders at a given timestamp to charge the driver for using the express lane.  

Source: http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2010/09/13/BA741FC1FI.DTL