Express Lanes, Flex Tags and the Lines You May Not Cross

US-101 down the Peninsula is one of the most heavily used commuter corridors in California, connecting San Francisco to the job centers of San Mateo and Santa Clara counties. Express lanes now run along stretches of it, and they trip people up for a simple reason: they are not carpool lanes and they are not toll lanes. They are both at once, and which one you are using depends on a switch on your transponder.

The basic bargain

An express lane lets a solo driver buy access to a less congested lane by paying a toll that varies with demand. Carpools that meet the posted occupancy requirement use the same lane without paying, or at a discount, depending on the facility. The price is displayed on overhead signs and changes through the day — that is the mechanism working, not a glitch.

The occupancy requirement, the hours of operation and the pricing are set by the agency running each facility, and they are not identical from one corridor to the next. Read the signs on the corridor you are actually driving rather than assuming the rules from another one.

The switchable tag is where people get caught

Carpool users need a switchable transponder — a FasTrak Flex tag — with a slider set to the number of occupants in the vehicle. Set it to 1 and you are billed as a solo driver. Set it to 2 or 3 and you are declaring a carpool.

Two failure modes are extremely common and both are avoidable:

• Forgetting to move the slider back to 1 after the carpool day ends. Declaring a carpool you do not have is a violation, and enforcement in these corridors includes officers checking occupancy against the declared setting.
• Leaving it on 1 with three people in the car and simply paying for a trip that was free. Nobody refunds that.

Set the slider before you pull out, every trip. It takes a second and it is the entire compliance burden.

The double white lines are enforceable

Where a lane is separated from the general lanes by double parallel solid lines, you may not cross them. Vehicle Code section 21655.8 provides that no person driving a vehicle may cross over these double lines to enter into or exit from the exclusive or preferential use lanes, and that entry and exit are permitted in areas designated for the purpose or where a single broken line is in place.

This is one of the most commonly written citations in these corridors and one of the least understood, because from inside the car the double line looks like paint rather than a rule. Wait for the broken line. If you miss your entry point, you missed it — the next one is coming.

What it costs you when it goes wrong

Two different things can happen and they are worth separating. An unpaid toll is handled as a civil toll evasion penalty under Vehicle Code section 40250, with the registered owner and driver jointly and severally liable, and unpaid penalties eventually reach your registration — Vehicle Code section 4770 requires the DMV to refuse renewal where a toll evasion notice has been mailed and remains unpaid.

A citation for crossing the double lines, or for declaring an occupancy you do not have, is a traffic citation and a different category of thing entirely. If you are unsure which one an envelope in your hand is, read what it says it is before you decide how worried to be.

The mileage point, since this is a commute corridor

A Peninsula commute is high-mileage by any measure, and Insurance Code section 1861.02(a) ranks annual miles driven as the second of California's three mandatory rating factors, behind driving safety record and ahead of years of driving experience. If you moved, changed jobs, or shifted to two days in the office, the number on your policy is probably stale. Nobody updates it for you.

Two minutes to get a current picture.