Vivian Lay

That's when we return.

Hi, good morning.

The ATSAC control room is located in downtown L.A.

in a huge glass building around the corner from City Hall.

It's a big space that looks kind of like a corporate meeting room with blue-gray carpet and a wall of glass windows where you can see traffic down below.

But the main attraction is the huge block of screens that stretches across the front of the room.

It displays live camera feeds of intersections across the city so that engineers can keep an eye on where congestion is building up and why it's building up.

This is Eric Zambon, a transportation engineer in charge of the ATSAC Center.

He gave Vivian a tour last month and talked her through the big screen and what it allows the engineers to see.

Gotcha.

On that same big screen, there's also a map of every traffic signal in LA.

They show up as multicolored dots of light.

As Eric explained, most of the traffic lights were working well, and they were running their usual timing.

It's that space-time problem again, as Salida Reynolds described it.

The ATSAC system has improved traffic in L.A., but it can't control the fundamental layout of the streets or the number of people using them.

It can't control the fact that L.A.

was built as one of the most car-centric cities in the world.

Engineers can play with time, coaxing millions of people through various bottlenecks.

But sometimes, no matter how advanced their algorithms, it's still kind of lipstick on a pig.

And they're still left with something like the Fairfax Asterisk, an intersection that just was not designed to handle so many cars.