San Anselmo using AI-controlled traffic lights at busy intersection
By John Ramos
A group of Bay Area entrepreneurs has paired artificial intelligence with traffic lights and may be blazing a trail to the future.
San Anselmo is a small town, but you wouldn’t know it from the intersection known as “The Hub,” where Sir Francis Drake, Red Hill and Center Boulevards meet. At 65,000 cars per day, it is the busiest intersection in Marin County. But that means a lot of waiting at red lights.
“They get complaints about this intersection,” said Collin Barnwell, CEO of Roundabout Technologies. “Residents have been telling them for years that they have a problem. It’s a difficult problem to solve without putting a lot of money into infrastructure, pouring a lot of concrete.”
But Barnwell and Chief Technology Officer Sabeek Pradhan may have solved that problem. Their startup company has extended the same kind of intuitive awareness of self-driving cars into traffic control systems. Normal systems use cameras to monitor cars coming from each direction.
“The controller is taking this input and saying, well, if something’s here, I should probably turn the light green for, like, 20 seconds because there might be more things there, there might not, I’m not sure,” Barnwell said. “And there’s a bunch of cars waiting here, a bunch waiting there, but the sensor says there’s one car here, so you keep it green.”
That leaves lines of traffic waiting at red lights for one, or sometimes no cars at all. But Roundabout’s electronic brain assesses the actual, real-time situation.
“Not just cars but every bike, bus, pedestrian, everybody that’s moving around, mapping them in a 3-D space,” said Barnwell. “And then we’re using that, positions and velocities, to run this real-time simulation 10 times a second. We can make any light change in the timing plan that’s allowed. What’s the best one for throughput and safety?”
They say the system is cutting time stuck in traffic at The Hub by about 30 percent, 91 hours of combined time for drivers, at a cost of 30 cents per hour to the city. And safety is improved because it takes bikes and pedestrians into account, as well. Google installed its own traffic system in Seattle, but it only uses Google Maps data to help engineers time their lights better. The Roundabout system monitors what’s really happening at any given moment.
“It makes a lot more sense if you can just see what’s actually going on and react to it in real time,” said Pradhan. “So, I do think that in a lot of ways this is the future. The main reason you didn’t see this 10, 20, 30 years ago is just because the same technology wasn’t there to allow you to see everything going on the way that we can today.”
The system has been operating since August and San Anselmo is the company’s first client. But the city has already gotten a grant to install the AI controller in all 12 of its stop lights. They say the reaction from residents has been positive, except for one complaint from someone who said they can no longer check their texts while waiting for the light to change.
“I’ve been really pleased at how we’ve been able to do everything and how well it’s been working in San Anselmo, so far,” said Pradhan.
The city says it is excited by the results and looks forward to coordinating the technology with other towns in the area. Some fear AI will be the downfall of mankind, but if it cuts time waiting in traffic, it might be worth the risk.
