The reason L.A.'s traffic is horrible but not impossible

It's all in the way stoplights are timed. For all the talk about monstrously expensive subway systems that will take decades to build and not even reduce traffic, it's the Automated Traffic Surveillance & Control system, or ATSAC, that keeps the cars moving. Specifically, it's the 18,000 magnetic sensors embedded in L.A. roadways. From Forbes:

A large digital leaderboard mounted on a wall shows intersections with unusually high congestion. If an intersection is under observation by one of the city's 400 live cameras (installed at the most troublesome spots), the operator can pull up video to see why things have gotten so bad. "We figured out long ago that an engineer can't scan 18,000 detectors continuously to see if a flashing red light is a problem," says Verej Janoyan, bureau chief in charge of the design and operation of the city's intersections. "This way, we've got one engineer overseeing 4,100 intersections."

The genius of the system--which the city calls Automated Traffic Surveillance & Control, or ATSAC--is that it's both automated and adaptive. As congestion builds on one street relative to another, it adjusts traffic-light cycles to give more green time to the congested lanes. At the same time ATSAC builds a rich database of historical traffic statistics used to adjust the timing of signals and to tweak intersection configurations across the system. ATSAC is smart enough to avoid overreacting to a momentary crush of cars. "Our system is designed around patterns," says Yu. "We need to have lots of data to evaluate so that we don't make changes that eventually worsen traffic."

An inquiring mind would like to know why the city doesn't focus more on this type of leading-edge technology instead of wasting its time - and considerable dollars - on a subway system that's based largely on century-old technology?