FasTrak Flex switchable transponder for use on the I-580 Express Lanes in California's Tri-Valley and Bay Area. This electronic toll collection device includes $30.00 in pre-paid tolls and features a small switch that allows drivers to indicate the number of vehicle occupants (1, 2, or 3+).

Carpools, vanpools, motorcycles, buses, and eligible clean-air vehicles with the transponder set to 2 or 3+ ride the I-580 Express Lanes toll-free. Solo drivers can choose to pay a toll for a more reliable trip. The express lanes operate Monday through Friday from 5 AM to 8 PM; all other times the lanes are open to all traffic with no toll tag required.

The FasTrak Flex transponder mounts to the vehicle windshield and is compatible with all tolled bridges, lanes, and roads throughout California. An account can be managed online at BayAreaFasTrak.org.