Just letting the cars set the light would not work for some of the plans with autonomous cars.
Currently with cars you need green-red periods. But some researchers are considering scenarios, where in the future the cars just reserve the intersection for a few seconds and then pass through. That would be a lot of flickering between green and red.
There are scenarios and simulations where they show that we can get a lot more (fuel and time) efficient if we just let cars pass by each other in these reserved time windows. In many of these scenarios cars just go over the intersection at full speed during their reserved time windows.
NOTE: I am just reporting on what I know other researchers are currently investigating and proposing. I am not saying I think this is a good idea. At least I would consider this a security nightmare, because hackers could very easily have cars crashing into each other at full speed. Also I would be very very worried passing through an intersection behind an autonomous car and just trusting that this car not only reserved their window, but also reserved some additional time for me.
> because hackers could very easily have cars crashing into each other at full speed.
Not just hackers. If we assume that cars would be weaving through the intersection at full speed, human drivers are going to do dumb stuff and cause high speed collisions. “Just fly through the intersection at 70 miles an hour… Follow the car in front of me… Make my left turn… CRASH.”
For that matter a dog running into the intersection is likely to cause a high speed collision. Implicit in the assumption that the time savings comes from this “fast flickering” and allowing cars to speed through the intersection in small windows is the fact that the safety margins are very small.
Currently with cars you need green-red periods. But some researchers are considering scenarios, where in the future the cars just reserve the intersection for a few seconds and then pass through. That would be a lot of flickering between green and red.
There are scenarios and simulations where they show that we can get a lot more (fuel and time) efficient if we just let cars pass by each other in these reserved time windows. In many of these scenarios cars just go over the intersection at full speed during their reserved time windows.
NOTE: I am just reporting on what I know other researchers are currently investigating and proposing. I am not saying I think this is a good idea. At least I would consider this a security nightmare, because hackers could very easily have cars crashing into each other at full speed. Also I would be very very worried passing through an intersection behind an autonomous car and just trusting that this car not only reserved their window, but also reserved some additional time for me.