Yeah, that are exactly the arguments used by companies selling "Intelligent Transportation Systems". After deployment: surprise - there aren't any noticeable changes, except for places that are performing worse and require manual tweaking. Also the best way to reduce traffic in city is to reduce vehicle flow into the city which only moves jams to other places.

Yeah, it's obvious there's a heluva lot of low hanging fruit in dynamically adjusting the traffic lights. Lots of them already even have cameras on them, it's just a software problem, and a problem worth scores (hundreds?) of millions to solve (in terms of gas, pollution, and time reductions).