How do I make it sound like that? You first need to build traffic light and road infrastructure that can handle advanced traffic flow, along with the processing power to make decisions based on sensor readings and rules.

The software (AI is kinda overkill) exists to handle and optimise traffic flow over an entire city, but your software does not matter if there are insufficient sensors for the software to make decisions, or too few controllable lights to implement decisions (or both).

What they're saying is if money was adequately invested in infrastructure, these old systems would have been upgraded 10 or 20 years ago and AI would not be necessary at all.