Report on April 2 AB 1581 Subcommittee meeting

The AB 1581 Subcommittee held its second meeting on April 2. Recall that AB 1581 requires that new and modified traffic actuated signals in California be able to detect bicycles and motorcycles, but only after Caltrans adopts guidelines for detection and signal timing. The AB 1581 Subcommittee will be presenting its recommendations to the

California Traffic Control Devices Committee to consider at its next meeting on May 29, 2008, in the CSAA building in San Francisco. The CTCDC in turn will recommend changes in the California Manual on Uniform Traffic Control Devices, which is administered by Caltrans. So actual changes are still many months and many meetings away. But the AB 1581 Subcommittee pretty much finished its work at the April 2 meeting.

Attending the meeting in person were Ahmad Rastegarpour, Kai Leung, Richard Haggstrom, and David Priebe from Caltrans, James Lombardo from ABATE (motorcycle advocacy), Damon Curtis from San
Francisco, and me. David Roseman from Long Beach and Sean Skehan from the City of Los Angeles attended by telephone.

The meeting was very productive and we agreed on the following recommendations:

1. Bicycle/motorcycle detection will be performance-based. At least 95% of bicycles and motorcycles that stop within the detection zone (defined below) shall be detected.


2. The default detection zone shall be a 6'x6' box at the the stop line centered within the lane, except that if the lane is more than 12' wide, the edge of the box shall be 3' from the lane line. If the detection system is capable of detecting bicycles and motorcycles anywhere within the default detection zone, then no marking is necessary.


3. A detection system that is capable of detecting the reference bicycle/motorcycle plus rider in a detection zone at least 3' wide but less than 6' wide shall be allowed, but only if a Bicycle Detector Symbol is placed at the center of the narrower detection zone.


4. The reference bicycle/motorcycle and rider shall consist of a folding bicycle with non-ferromagnetic frame and 16" wheels with aluminum rims and stainless steel spokes, such as the Dahon Curve SL, plus a person 4' tall weighing 90 pounds standing over the bicycle.


5. To be allowed for use at actuated traffic signals in California, a detection system will need to be certified by its manufacturer to meet the performance requirements of detecting the reference bicycle/motorcycle and rider stopped in either the default detection zone or the narrower detection zone at least 95% of the time under actual operating conditions.


6. For the purposes of setting up the detection at a new or modified signal, a signal technician may choose to use an equivalent rim/rider consisting of a 20" BMX aluminum rim mounted in a wooden frame and set vertically 1.5" above the pavement plus a plywood cutout representing a person 4' tall weighing 90 pounds standing over the rim.


7. Caltrans will approach manufacturers of carbon fiber rims to request that they either include a shorted coil of wire in the rim during the manufacturing process or else attach a sticker notifying the user that the rim will not trip inductive loops at traffic actuated signals.


8. The minimum green time at traffic actuated signals shall be long enough such that, when combined with the yellow and all-red times, most bicyclists starting from a stop at the beginning of green will have enough time to substantially clear the intersection.


9. The Subcommittee decided not to address the all-red time as a separate issue. Their reasoning was that CVC Section 21451 already requires that drivers facing a green signal "shall yield the right-of-way to other traffic and to pedestrians lawfully within the intersection or an adjacent crosswalk." Thus bicyclists who enter an intersection toward the end of yellow (which is legal in California) may not have enough time to substantially clear the intersection before conflicting traffic receives a green signal.

I presented these recommendations to the California Bicycle Advisory Committee the following day. CBAC made some helpful suggestions, one of which resulted in a refinement of the reference bicycle/motorcycle definition. CBAC also decided to address the issue of the many traffic actuated signals that are not addressed by AB 1581 by recommending to the CTCDC that the CA MUTCD provide for a 10 year compliance period for all signals in California to meet the recommended bicycle/motorcycle detection guidelines.