The Elephant in AC’s Board Room

It is just a baby elephant now, patiently swaying in a back corner. No one at AC dares mention it, though the same calf is waiting in the wings of every board chamber at every US bus transit agency. For these agencies, the elephant is the now common understanding that it is just a matter of time, perhaps less than ten years (sooner than when our newest buses will be retired), before the general public recognizes that autonomously driven buses would be safer for pedestrians, bicyclists, car passengers, and all other users of the roadway.

The old adage that equates personal disaster with being “hit by a bus” is in fact apt. Empty transit buses weigh between 10 and 16 tons, and when fully loaded can weigh 22 tons. That is good for the passengers on the bus, as they are well protected in the event of collision. But even at a slow speed, whomever is hit by a bus is too often met with life-crushing force.

Enabling these heavy vehicles to stop in an emergency is a difficult engineering task, and the drivers of these huge vehicles that are being driven down busy streets, surrounded by ever more distracted pedestrians and other drivers, must be lightning quick. Driving an urban transit bus is an arduous job for a number of reasons, but the greatest toll is taken by the extended hours during which they are forced to be on high alert.

For this reason alone, transit buses are ideal candidates for autonomous driving technology. A computer would know, not only generic driving, but the particularities of its encoded route, from its own “experience” as well as that of all the other buses that have served that route. Gradually, drivers would become more like conductors, able to direct most of their attention to passengers.

Today’s transit agency boards ignore the elephant, fearing their drivers union more than the public. But the calf will mature with the public’s growing confidence in autonomous driving technology. Continued ignorance means that AC and the other agencies will eventually have to answer for outdated practices that so endanger fellow road users.  My goal is to have a transition plan formulated over the next four years. Each of our buses already utilizes several external cameras, but they are all passive recorders. Formulating a probable timeline and transition plan must begin now. A new bus costs AC about $750,000. Why can’t AC begin the transition by requiring that its new buses utilize those cameras in the driver assist mode, a technology available in new cars that cost as little as $35,000? Our Gillig buses are made right in Hayward. Why can’t AC start work now with Gillig to accomplish this simple first step? These are among the first questions the Board should begin addressing.

Transbay Terminal News

PISA, ANYONE? No doubt you have probably heard of our 58 story sinking and leaning tower next door. One of the things I want is for the TJPA be absolutely transparent about what it knew, when it knew it, and who it told about the problem. Already it has taken a big step toward that as you might tell from our press releases to date:

At the next TJPA board meeting though, I intend to propose that the TJPA take a further step by making available on its website every single document that it delivers or discovers through the litigation or in response to a Freedom of Information Act request. The TJPA is a public agency, so what it knows or discovers, the public should be able to easily discover. The process of discovery, and fights over discovery, is what drags litigation out. I’ m hoping that by making everything known early, the litigation might end sooner. Fortunately for the TJPA, between its contractual indemnification rights and its own liability insurance, whatever happens it is well protected.

It may be though that if most of the liability cannot be pinned on others, some group of investors are looking at hundreds of millions of dollars in financial exposure, with much of that uninsured. For them, if bankruptcy is foreseeable, the litigation costs are minor in comparison to those loses, so ala-Trump they may choose to litigate for a long time before conceding.

How to Really End Bus Bunching


Bus bunching is the phenomena of two or more buses on the same route being too close together. My opponent is going around saying that AC Transit need only implement “headway-based scheduling” to eliminate the problem of bus bunching.

In “clock scheduling”, each driver tries to be at given points on the route at specific times, according to the published schedule. With headway-based scheduling, the published schedules only say that buses will be along every X minutes, so drivers need to know how to maintain that interval. Headway based scheduling makes sense for short circulator routes and frequent express routes such as San Pablo Avenue’s 72R and International Boulevard’s upcoming Bus Rapid Transit line. However, it is no solution to the problem of bus bunching because it requires special route infrastructure to implement properly, and even perfect implementation actually worsens average passenger travel times.

Bunching occurs on high frequency lines when Bus A initially gets behind its fixed schedule due to some unusual circumstance such as loading and unloading several wheelchair passengers, or encountering a traffic accident. Short initial delays can grow quickly over the rest of the route because the “dwell time” at each stop gets ever larger with increased passenger boarding and discharging. As a result, Bus B eventually catches up to Bus A; and for the 51A, even Bus C might eventually catch up. That is why bunching usually occurs toward to end of a line.

My opponent’s solution is to program a computer to anticipate the bunching and somehow make Bus B slow down by waiting at the stops. How much to make it slow down, and when to have others begin slowing down, requires that the computer not only know the exact location of each bus, but have the ability to communicate increasingly frequent slow down commands to following drivers. Right now, AC Transit’s NextBus real time arrival predictions are not reliable enough for the former, and have no means of doing the latter. But even if those capabilities did exist, it would only be to the detriment of Bus B’s passengers.

After Bus A slows to a point where the computer begins telling B’s driver to slow down, B’s riders then get to sit at stops for no apparent reason, suffering longer trip times. And those waiting at stops immediately ahead of B get to wait that much longer. Tragically, all of that waiting does nothing to relieve the riders already suffering on Bus A. With bunching, at least those B riders who boarded early and get off before B meets A, have normal trip times.

In actuality, the only reason to prevent bunching by slowing B early is political. For observers on the street it may be less embarrassing to AC, but it comes at the cost of less efficient bus service for its riders.

The real solution is one I conceived and call “bump and run” in which Bus B’s driver, upon catching up to Bus A, passes A and begins boarding passengers from the upcoming stops; giving those passengers an earlier bus because, unlike A, B is not over-loaded with passengers needing to be discharged. Similarly, Bus A’s passengers, waiting for discharge, get a faster ride because the upcoming stops are free of boarders.

The only decision required for this solution is determining whether Bus B’s driver can assume Bus A’s schedule for the return trip, or even the rest of the shift, should she so desire. That would require a protocol to be developed by the driver’s committee that works with AC operations management. And that protocol probably needs to wait until AC has its new more accurate GPS system in place next year, so schedule switches can be automatically tracked. I hope to keep working with our scheduling department and the A.T.U to see that done.


I am running for election to a 5th term as AC Transit Director for Ward 2 (Berkeley, Oakland, Emeryville, Piedmont). If re-elected, most of my posts will be devoted to apprising readers of important issues before and decisions by AC Transit and the Transbay Joint Powers Agency, on which I now serve as chair.

From the outset, I want to include how those issues and decisions fit into local, state, and national politics. Eventually, I would like to broaden the discussion into local, California, and national politics in general.

We have to come to grips with the dysfunctionality that has seized national politics, and consider its possible consequences. Other than with respect to judicial appointments, I am not sure that even a Senate takeover by Democrats will much alleviate the seizure. For transportation development, the seizure will be transformative at best and catastrophic at worst; and I fear that other areas of public policy will fare the same.

For the next few weeks though, my mode of transit will be that of floating down the South Fork of the Flathead River through Montana’s Bob Marshall Wilderness. In late August, I plan to start posting. If you are interested in the conversation, please sign up for the ride.

Greg Harper