In my experience, if there was a well-defined problem in the 70s or 80s, some clever person came up with a workable solution using a tiny microprocessor with limited RAM.
The way I think about it is... when I was a kid I hated waiting at lights and imagined you could build a computer vision/ML system (this was in the '80s) that coudl recognize traffic and change the light to green when it was safe, rather than timing out. I mentioned this to some traffic engineer and he pointed out the simpler solution was to put magnetic detectors under the road and then just look for blips which are cars driving over.
And then someone rolls up with a bicycle, and because it doesn't have as much metal in it as the detector expects, they end up sitting at a red light forever. Been there, done that.
My local town has a roundabout with a cut-through lane for buses. The cut-through has a traffic light to help the bus emerge. Every so often, a (presumably non-local) car driver accidentally enters the bus lane, and then has to wait for the next bus to trigger the traffic light.
The way I think about it is... when I was a kid I hated waiting at lights and imagined you could build a computer vision/ML system (this was in the '80s) that coudl recognize traffic and change the light to green when it was safe, rather than timing out. I mentioned this to some traffic engineer and he pointed out the simpler solution was to put magnetic detectors under the road and then just look for blips which are cars driving over.