Ease traffic congestion by getting rid of traffic waves.
We would have our cars tell us a specific speed to drive when doing so temporarily would clear out traffic waves and let us speed back up to normal for the road.
Let's say that traffic waves are causing an average speed of 25mph on a highway where the speed limit is 65mph. If you can get most people to drive 15mph for a few minutes, it will clear out the traffic waves and you'll be back up to 50+mph in no time.
There have been previous attempts to get at this problem, such as roads with variable speed limits directed by electronic signs. Such solutions have been only marginally effective; people find them confusing and the fixed locations of these roads associate them with speed traps.
What has changed? Timing, convenience, cost. Our devices and networks are now fast enough to put this in each vehicle. Location information is more precise. People are used to getting driving information from screens. Many already have a screen set up.
The only information this system would display onscreen for each vehicle is the ideal speed to drive, when useful and where available.
Enough participants would be needed to control the flow of traffic for people who are out of signal or who aren't participating.
While I would love to see an end to traffic congestion, and it would seem that technology may soon make this possible, certainly in models within the next five to seven years to work out the bugs in the prototypes, so that by 2050 our highways and traffic movements might look as they do in the movie "Minority Report."
However, there is that pesky human element to contend with. For example, the person that avoids waiting in a line of backed up traffic and shoots by to the very end, although I have seen that to be an affective way to avoid those backed up highway lanes shifting to fewer or single lanes, this is a driver that bothers those who will stay in their lane even if the other drivers must wait in the line and who think it moralistic to do so.
But there are other impatient drivers too, like the lane weavers, wannabe race car drivers, and others, all with their own idiosyncrasies blasting through sub-woofers alongside of the families, road warriors and semis. All of these folk would and their vehicles would, through the use of technology, be subjected to a federally mandated highway control system that should also cover every other environment like secondary and tertiary roadways. That is as long as no one flips their switches off. Call it a sort of anti-road rage, control system.
But even though people will quite likely never change, the system such as of what you speak of, I believe, is entirely feasible given the ever increasing applications of AI and the Moore's Law, I could see this in my lifetime. Although, once society has fully adapted of to a fully automated, automobile navigation and control system we may well be on our way to resembling the passengers on the spaceship liner in the movie "W.A.L.I.."