Two things that I see as problems with this type of system: pedestrians/nonmotorized users, and the need for 100% of vehicles to be on the system. Starting with

Two things that I see as problems with this type of system: pedestrians/nonmotorized users, and the need for 100% of vehicles to be on the system. Starting with pedestrians, it is important to have adequate crossing time for a pedestrian for obvious reasons. The current standard in the US is to assume that the pedestrians are walking a 3.5 ft/s. This sounds slow but it is meant to account for elderly/disabled individuals. Using this speed, a pedestrian clearance interval is calculated. This value is commonly used as the minimum green time for a signal phase that includes a pedestrian phase. Even without a pedestrian call, pushing the button, this time is used. The reasoning behind this is due to the possibility of a pedestrian crossing without press the button first. This issue can likely be overcome through some fancy algorithms and pedestrian detection. However, you really want your ped detection to be perfect since one missed detection can easily result in a fatality. The second issue, 100% of vehicles on the system, is more insurmountable. How many vehicles do you see on the road that are older than 5 years? 10 years? 20 years? Quite a few. Many of the people driving those cars fall into two categories, those that can't afford a newer car or collectors. Those that can't afford a newer car likely cannot afford to retrofit their existing car with V2V hardware. The second group, collectors, likely don't want to install aftermarket electronics into their vehicles. The presence of cars without the necessary equipment may result in very severe consequences for the system. My opinion on improving traffic flow through a network is that improvements to a centralized monitoring system will work better and be more resilient to edge cases. With a centralized system, it is easier to ensure that it is operating as it was designed. If you have tens of thousands of individual systems all trying to operate in concert, it could only take a few to cause havoc. Bad actors and poorly operating units will happen.