Comment by Tangurena2

> There are already cameras on top of all the lights.

Those are infrared sensors that pick up the heat from car engines. They've had to be modified to pick up electric cars.

> How hard can it be to hook them up to AI that is instructed to maximize throughput?

The equipment cabinet at the intersection has been engineered to prevent all sorts of fatal things that happened in the past. Such as one set of relays being stuck so that one direction always gets a green light while the other direction gets red/yellow/green. They're designed so that can never happen again (when "broken", you'll see blinking red in all directions).

The controllers need to be standardized so that you don't need experts to be able to diagnose & repair them. They also need to be certified. It is not possible to certify an expert system (or as they're now called "AI") because it is not possible to use formal methods to prove correctness.

> The current system will block 3 directions while having a green light on the 4th which has no traffic.

That specific intersection is set on a timer. For a single, 2-lane each way, non-complicated intersection, it can cost $100k for the lights, poles, sensors and equipment cabinet. Every wire is underground in pipes so that the expansion of concrete in weather won't stretch/break the wires.

> as drivers simply cooperated with each other.

That's something that most people learn in kindergarten: "share with others" and "take turns".

Where I live (fly-over country), when the power is out, traffic backs up significantly.

Disclaimer: I used to work for my state's combination DMV & highway department.