AI-Boosted Traffic Signals Cut Waits in San Anselmo

Published Date : 16/10/2025 

A pilot program using artificial intelligence in San Anselmo has significantly reduced vehicle delays at a notoriously congested intersection, improving traffic flow and reducing frustration for drivers. 

A pilot program using artificial intelligence in San Anselmo's traffic light system has reportedly reduced vehicle delays by more than 30% at a problematic intersection, town officials said.

The intersection of Sir Francis Drake Boulevard, Red Hill Avenue, and Center Boulevard, known as The Hub, has been a long-standing traffic bottleneck. The new system, which includes additional cameras and a small server inside the traffic signal box, uses computer vision software to track the exact position and speed of every vehicle in real time. This data is then used to adjust the signal timing, ensuring traffic flows more efficiently.

“It’s like having a live human being look down the street, and instead of waiting for a timer to change, it looks down the street to see if there are no cars, or cars coming faster or slower,” said San Anselmo public works director Sean Condry.

According to Scott Schneider, San Anselmo’s assistant public works director, the AI system reduces approximately 90 hours of vehicle delay per day. This translates to 15 seconds saved per person, multiplied by the 65,000 vehicles that pass through the intersection daily.

The data comes from Roundabout Technologies, the company that created the system. However, the town has contracted with a consultant to verify these findings by comparing new and old data.

“We have received many positive comments that the system works so well now that people can no longer sit there and text or do emails at the intersection,” Condry noted.

The old system would allocate a fixed amount of time to each direction, regardless of the actual traffic flow. In contrast, the AI system can differentiate between cars and public buses, and the company plans to add features that detect pedestrians and cyclists.

Schneider emphasized that the cameras do not record video, nor do they include face detection or license plate reading. Two to four new cameras are required at each intersection, and a cellular connection enables each AI server to communicate with others for coordinated operations.

The system has been operational for about one to two months, with installation completed before the start of the school year. Another system has also been installed on Bank Street, about a block away.

Ongoing monitoring costs are approximately $12,600 per year for 24/7 monitoring, support, and updates. The initial installation at The Hub cost about $30,000, while the system at Bank Street will cost $10,000 for installation and $4,600 annually for monitoring and optimization.

While Schneider acknowledged that a roundabout with a pedestrian flyover bridge could potentially reduce wait times even further, he noted that such a project could cost between $40 to $50 million. “A roundabout could probably dramatically decrease wait times and do even better, but this AI has proved to be remarkable in the improvements that we’ve noticed,” he said.

The town recently received a $250,000 grant from the Transportation Authority of Marin to install the system at the town’s other 10 traffic signals, as well as one in the town of Fairfax. These installations are expected to be completed over the next six months.

“We might be the first jurisdiction in California that has all of our intersections controlled by AI, but we only have 12 traffic signals,” Condry said. 

Frequently Asked Questions (FAQS): 

Q: What is the main benefit of the AI traffic light system in San Anselmo?

A: The main benefit is a significant reduction in vehicle delays, with the AI system reportedly reducing wait times by more than 30% at the intersection known as The Hub.

Q: How does the AI system work to reduce traffic delays?

A: The AI system uses computer vision software to track the exact position and speed of every vehicle in real time, adjusting the traffic signal timing to keep traffic flowing efficiently.

Q: What is the cost of installing and maintaining the AI system?

A: The initial installation cost at The Hub was about $30,000, and ongoing monitoring costs are approximately $12,600 per year for 24/7 monitoring, support, and updates.

Q: Are there any privacy concerns with the AI system's cameras?

A: No, the cameras do not record video, nor do they include face detection or license plate reading. They are used solely for traffic management purposes.

Q: What other intersections in San Anselmo will receive the AI system?

A: The town plans to install the AI system at its other 10 traffic signals, as well as one in the town of Fairfax, over the next six months. 

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