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If a car crosses through an intersection after a light-signal change, but no police officer is around to see it, does it create traffic mayhem?

A theory, posted on a thread in a Seattle forum on Reddit, is that using more traffic-control officers at busy intersections would better move traffic through the city during peak travel times.

“Honestly the intersections with Dexter, 8th, 9th, Westlake, Terry, Boren, and Fairview all need to have police directing traffic during rush hour. 6th & Battery too,” a user said on Reddit.

Traffic Lab is a Seattle Times project that digs into the region’s thorny transportation issues, spotlights promising approaches to easing gridlock, and helps readers find the best ways to get around. It is funded with the help of community sponsors Alaska Airlines, CenturyLink, Kemper Development Co., NHL Seattle, PEMCO Mutual Insurance Company, Sabey Corp., Seattle Children’s hospital and Ste. Michelle Wine Estates. Seattle Times editors and reporters operate independently of our funders and maintain editorial control over Traffic Lab content.

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But Shalom Hakkert, a professor in transportation and civil engineering at Technion in Haifa, Israel, said police resources are better spent enforcing safe driving, rather than directing traffic.

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As part of our Traffic Lab series of Q&As, we’re spotlighting the most effective means to ease gridlock during rush hour traffic.

The city of Seattle relies on traffic cops to direct cars around construction projects, special activities such as sporting events and the Women’s March, as well as for traffic incidents and signal outages, said Seattle Department of Transportation (SDOT) spokesperson Mafara Hobson. Large office buildings and companies, for instance, are permitted to hire traffic officers, she said, to manage the flow of vehicle and pedestrian traffic outside their parking garages during rush-hour times.

“However, should there be a dire need, I can’t imagine that we wouldn’t consider it or some other measure to help with traffic flow,” Hobson said.

Physical presence of police alone isn’t a strong deterrent, Hakkert said. The public needs to see them doing something, such as catching criminals, stopping speeders or monitoring overweight trucks.

“If you put police in the middle of an intersection on a raised pedestal, they will catch more violators,” he said. But in reality, no jurisdiction has a big enough police force to place officers at every busy intersection.

It’s generally better to solve issues through engineering than with police, Hakkert said. Red-light cameras and traffic-monitor radars are some such examples.

Bill Malkes, co-founder and CEO of GridSmart, a camera-sensory technology company that feeds information from intersections to traffic controllers, said traffic professionals get frustrated when the police take over intersections.

“Because you’re human,” he said. “You’re fallible in your logic and your thinking.”

With the right knowledge and right technology in place, “the computer is always going to make better decisions in moving you through,” he said.

The key is accurate detection.

For Mercer Street, a particularly busy road downtown, SDOT plans to install ramp-metering signals at the northbound and southbound freeway entrances before merging onto Interstate 5.

They will operate weekends only starting March 10 and then every day beginning April 10.

Got a question?

If you have a question or idea for Traffic Lab, send it to trafficlab@seattletimes.com. We may feature it in an upcoming column.