The last of the city's nearly 4,400 traffic signals were synchronized yesterday, marking completion of a project designed to lessen the amount of time that drivers spend in gridlock.

The Automated Traffic Surveillance & Control system, a $410 million effort to coordinate traffic signals across the city under a centralized system, could reduce the average amount of time drivers spend in traffic by one day per year, according to city transportation officials.

Synchronization is designed to increase travel speed by 12 percent, while decreasing the time spent stuck in traffic by 16 percent, according to Jaime de la Vega, general manager of the Los Angeles Department of Transportation.

The system coordinates traffic not only for vehicles, but also for pedestrians, cyclists, and public transit. Transportation engineers can monitor traffic remotely through cameras throughout the city, make adjustments to signal timing and analyze traffic data to improve traffic flow. Police and emergency vehicles will also be able to take advantage of the new system.

The signals can be programmed to respond to unusual traffic scenarios involving crowd-heavy events at major sports and convention venues like the Los Angeles Memorial Coliseum, Dodger Stadium, and Staples Center.

"As of today, we have synchronized every traffic signal in the city of Los Angeles," said Mayor Antonio Villaraigosa, who was on hand at the intersection of South Broadway and Martin Luther King Boulevard to turn on the final traffic signal in the system.

He also commended the effort for potentially reducing the level of greenhouse gas emissions in the city, since vehicles will be less likely to idle and emit exhaust.

"By synchronizing our traffic signals, we will spend nearly a day less (per year) waiting and reduce pollution by nearly a metric ton of carbon every year," Villaraigosa said.

The synchronization system was first proposed prior to the 1984 Olympic games held in Los Angeles. But the project lapsed until 2005, when Villaraigosa lobbied for the allocation of $150 million in Proposition 1B money to complete the program.