I have written before about the selfish merge which is a tricky problem to solve. One lane vanishes, and the merge brings everybody to a standstill. Selfish drivers zoom up the vanishing lane to the very end and are let in by other drivers there, causing the backup. The selfish strategy is the fastest way through the blockage, yet causes the blockage.

My thinking on Burning Man Exodus made me wonder if we might have a robot signal drivers not with lights but with radio. At the merge point we would place a computer with a radio transmitter, and detectors to measure the speed of traffic in each lane. If traffic flowed at a good speed, it would do nothing. If traffic slowed, signs would light up saying "Tune to and Obey AM 1610. $500 fine for lane changing without clearance."

The robot would be at the merge point, and also have traffic lights marked with lane numbers of names.

The radio robot would then move the lanes through the merge. The key is the robot can tell an entire lane to start moving slowly simultaneously, and to stop simultaneously, even over a longer distance. So it can command the left lane to start moving and the others to remain stopped and not to change lanes. When the left lane has emptied, it can command it to stop and the red light for that lane would go on (clearly visible at the merge point.) A camera could record anybody running the red light or changing lanes into that lane as it is emptying. As it is clearing, the radio voice can tell the next lane to prepare to move, and give it the green light and the verbal command to do so. Lower priority would be given to the lane that is vanishing and those stuck in it -- they were supposed to do a nice zipper merge a mile back, and are only stuck in it because they didn't do so. This means that zooming up in the vanishing lane becomes punished rather than rewarded, and as a result, this jam-clearing approach would be needed far less.

The system would have to be experimented with and tuned for the best results.

There is a problem that there has to be some point where the system starts, after which lane changes are forbidden. There is a risk that a jam could be created there rather than at the physical merge point, by people in the vanishing lane trying to get into to continuing lane. This is the parameter we would tune -- how much punishment can we give the people who wait too long in the vanishing lane before they start creating a jam a bit further up the road? Perhaps no punishment is needed, just equal treatment.

Of course there are two types of merges. Some are temporary, due to construction. Others are permanent. I am primarily aiming at the temporary ones here though it's possible that solutions could be found for permanent merge-jams. However, in permanent merges, drivers get to know the parameters and will try to game them. If we move where the merge is it's hard not to simply move the jam.

There is also the question of the very few cars without radios, and those who can't understand basic instructions in the languages given on the radio. (The instructions can be said in up to 3 languages, I would think.) Such drivers would have to just follow the other cars, which is doable, even if their reaction time will not be as quick. Drivers who can't read the signs already face the risk of violating traffic laws, of course.

I also don't know how much gain you get from everybody being able to stop and start at once on voice command. Obviously moving cars need wider spacing than stopped cars, so you can't actually start everybody at once like a train. Still, I think it should be possible to drain a blockage faster with the combination of coordinated starting and nobody else being allowed to merge into the lane during the period.

It's also possible the voice could tell cars in the vanishing lane to simultaneously enter the continuing lane once it has been cleared, but that requires a way to stop oncoming traffic from entering that lane during that process, and it's easier if all equipment can be placed at the merge point.