Octa's transportation blog

OC Traffic Light Synchronization, Explained

Shared from the popular Orange County Register column, “Ask Honk”

Q. Dear Honk: My hope for the holidays is that Santa asked the powers that be to fulfill the great promise to coordinate all of the traffic signals in Orange County so that we can all save a significant amount of time and fuel. I have asked Santa every year for this for the last decade. Babe, this is the year.

– Manny Levine, Anaheim

A. Well, let’s see if Santa brought you a nice gift, Manny, or just some lumps of coal.

There are roughly 3,200 intersections with traffic signals in Orange County, not counting Caltrans’ lights.

Of those, 2,700 have been synchronized since 2008, with the $54 million price tag covered by the county’s transportation sales tax, which costs us a half-cent for every taxable dollar spent.

As you can tell by the cash used for synchronization, it isn’t a matter of a worker just pulling a screwdriver from his tool box and twisting a screw to make a green stay on longer.

The goal had been 2,000 intersections by 2041, so thumbs ups are in order for transportation officials and their workers.

It is unclear how many more signals will get synced.

“Traffic signals are timed across city, county and Caltrans boundaries to allow for optimal travel times,” Eric Carpenter, a spokesman for the Orange County Transportation Authority, told Honk in an email. “That doesn’t mean no red lights, but it does mean more green lights, less time idling in traffic, and therefore cleaner air.

“Overall, travel speeds increase by about 14 percent (and emissions are reduced),” Carpenter said. “In the past, cities typically performed their own analysis and set up their own timing plans and cycle lengths without regard to what was happening across the border with neighboring cities. …

“A nearly $5 million effort is underway to synchronize signals on Katella Avenue, encompassing about 20 miles with 73 intersections across seven cities and county territory from Anaheim to Los Alamitos,” he went on to say.

All will not be smooth sailing, because:

  • Many streets were not built with synchronization in mind, so the spacing between intersections isn’t lined up perfectly.
  • Traffic on cross streets can’t be kept waiting too long at red lights.
  • Walkers’ and bicyclists’ needs must be figured into the math of it all.
  • Congestion can throw the flow off as well, of course.