Traffic Issues

The Automated Traffic Surveillance and Control (ATSAC) System developed and managed by LADOT is a national award winning interconnected and coordinated signal system.

System Size
The system includes 4,398 signalized intersections that control over 6,000 centerline miles of city streets. LADOT operates and maintains the system on city streets, state highways within the city’s geographic boundaries, and certain intersections in other municipalities and the incorporated part of Los Angeles County. The system includes over 25,000 vehicle detectors and over 450 cameras.

Signal synchronization was developed in-house by LADOT engineers. The initial system was deployed around the Coliseum to improve the efficiency of the city’s road network during the 1984 Olympics. (The system is referred to in-house as “ATSAC” – or “Automated Traffic Surveillance And Control”.)

LADOT completed the connection of every signalized intersection to the system and began operations of the final implementation area in February 2013. Field studies for the last sub-region were completed in January and February 2013. Upgrades, refinements, and improvements to the system will continue.

For more information about LADOT’s signal synchronization system, please contact our communications office at or (213) 972-8470.

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