Virtual right-of-way alternatives for BRT
In one of my first blog posts, I wrote about virtual right-of-way, a plan to create dedicated right of way for surface rail and bus transit, but to allow cars to use the RoW as long as they stay behind, and never in front of the transit vehicle.
I proposed one simple solution, that if the driver has to step on the brakes because of a car in the way, a camera photographs the car and plate, and the driver gets a fat ticket in the mail. People would learn you dare not get into the right-of-way if you can see a bus/train in your rearview mirror.
However, one downside stuck with me, which is that people might be so afraid of the ticket that they make unsafe lane changes in a hurry to get out of the way of the bus, and cause accidents. Even a few accidents might dampen enthusiasm for the plan, which is a shame because why leave the RoW vacant so much of the time?
San Francisco is planning BRT (Bus Rapid Transit) which gives buses dedicated lanes and nice "stations" for Geary St., its busiest bus corridor. However, that's going to cut tremendously into Geary's car capacity, which will drive traffic onto other streets. Could my plan for V-Row (Virtual Right of Way) help?
My new thought is to make travel in the V-Row a privilege, rather than something any car can do as long as it stays out of the way of the bus. To do that, car owners would need to sign up for V-Row access, and purchase a small receiver to mount in their car. The receiver would signal when a bus is approaching with a nice wide margin, to tell the driver to leave the lane. It would get louder and more annoying the closer the bus got. The ticket would still be processed by a camera on the front of the bus triggered by the brakes.
Non-registered drivers could still enter the V-Row, whether it was technically legal or not. If they got a photo-ticket, it might be greater than the one for registered drivers who have the alerting device.
I've thought of a few ways to do the alert. If there are small, short range radio transmitters dotted along the route, the bus could tell them to issue the warning as they approach. They could also flash LEDs (avoiding the need for the special receiver.) Indeed, they could even broadcast on a very low power open FM channel, again obviating the need for a special device if you don't mind not running your stereo for something else. (The broadcast would be specific, "Bus approaching on Westbound Geary at 4th ave" so you are not confused if you hear a signal from another line or another direction.) Infrared or microwave short-range transmission would also be good. The transmitters would include actual lat/long coordinates of the zones to clear, so cars with their own GPS could get an even more accurate warning.
It might even be possible to have an infrared or ultra-high-frequency radio transmitter on the front of the bus, which would naturally only transmit to people in front of the bus. IR could be blocked by fog, radio could leak to other zones, so there might be bugs to work out there. The receiver could at least know what direction it is going (compass, if not GPS) and know to ignore signals from perpendicular vehicles.
Each bus of course, via GPS will know where it is and where it's going, giving it the ability to transmit via radio or even IR the warning to clear the V-Row ahead of it.
V-Row is vastly, vastly cheaper than other forms of rapid transit. In fact, my proposal here might even make it funded by the drivers who are eager to make use of the lane. Many would, because going behind the bus will be a wonderful experience compared to rush hour traffic, since the traffic lights are going to be synchronized to the bus in most BRT plans.
One could even imagine, at higher pavement cost, a lane to pass the bus when it stops. Then the cars go even faster, but the driver signals a few seconds before she's going to pull out and all cars in the lane would stop to wait for it, then follow it. Careful algorithms could plan things properly based on bus spacing and wait times and signals from drivers or sensors to identify where the gaps in the V-Row are that will allow cars are, and to signal cars that they can enter. (The sensor would also, when you're not in the V-Row, tell you when it's acceptable to enter it.)
During periods of heavy congestion, however, there may not be anywhere for cars leaving the V-Row to go in the regular lanes without congesting them more. However, it's not going to be worse there than it is with no cars allowed in the bus right-of-way, at most it gets that bad. It may be the case the bus drivers could command all cars out of the V-Row (even behind the bus) because congestion is too high, or transit vehicles are getting too closely spaced due to the usual variations of transit. (In most cases detecting transit vehicles that are very close would be automatic and cars would be commanded not to enter those zones.)
There are many other applications for a receiver in a car to receive information on where to drive, including automatic direction around congestion, accidents and construction. I can think of many reasons to get one.
Some BRT plans call for the dedicated right-of-way to have very few physical connections with the ordinary streets. This might appear to make V-Row harder, but in fact it might make planning easier. Cars could be allowed in at controlled points, like metering lights, and commanded to leave at controlled points. In that case there would be no tickets, except for cars that pass an exit point they were commanded to leave at. If the system told you to stay in a lane and was wrong, and a bus came up behind you, it would not be your fault, but nor would it be so frequent as to slow the bus system much.