Saturday, July 20, 2024

Petru Sofio notes traffic trends at Massachusetts Avenue at Beech Street in North Cambridge in August. (Photo: Jan Devereux)

On a recent Saturday morning I spent a couple hours on the corner of Massachusetts Avenue at Beech Street with Petru Sofio observing how people move through the busy intersection. I had never met Petru in real life before, but I have been one of his legion of Twitter followers for almost two years. He posts and comments prolifically and shares photos of streets all over Camberville and Boston and other cities he visits. Based on his command of traffic safety principles and technical design standards, I had assumed he must be a transportation professional. When I later heard him described as a student, I thought he might be a grad student at MIT. It was only a few months ago that I realized Petru is still in high school.

In fact, Petru, who just turned 17, will begin his junior year at Arlington High School this week. Despite our more than four-decade age difference, I was Petru’s student that morning. Standing on the corner with Petru and listening as he narrated the movement of all modes from all directions, I learned to understand the intricate choreography of the signals and to appreciate Petru’s mastery of the dynamic interplay of signal operations, human behavior and transportation safety.

Petru will have to miss most of the first week of school to attend the National Association of City Transportation Officials “Designing Cities Conference,” which will draw more than a thousand transportation planners and practitioners from all over the country to attend workshops and site visits in Boston, Cambridge and Somerville. Petru will be at NACTO representing MassBike, where he interns as a design review intern.

Safe to say, Petru will be in his element at the conference. Fascinated with traffic signals for as long as he can remember, Petru began drawing pictures of streetlights as a small child. He says the first sentence he wrote was “No turn on red” – he had to ask his father to help him spell the words. Petru was 3 at the time. He’s been watching and learning how streets work ever since.

Petru has an intuitive grasp of how streets work, and an encyclopedic memory for signal timing. He told me that he knows the phasing of every traffic signal in Cambridge, Arlington and Somerville and maybe Belmont, too. This was not meant as a boast. An important thing to know about Petru is that he is one of the most self-effacing and generous super-smart people you’ll ever meet – in person and on social media.

While he is not yet old enough to vote, Petru has expertise that has earned him a seat at the table in traffic safety discussions. His advocacy began following the May 2020 death of cyclist Charlie Proctor on Massachusetts Avenue at Appleton Street in Arlington, near where Petru and his parents live. The intersection has since received some short-term improvements. While these changes might have protected Proctor and the partner biking with him, the town is soliciting public input on the more extensive changes that safety advocates such as Petru and MassBike have recommended for the intersection.

This year Petru played an integral role in persuading the city’s transportation staff to install what’s called a “leading bicycle interval” signal for cyclists heading both directions on Massachusetts Avenue at Beech Street as part of the Porter Square safety improvement project. This gives cyclists a seven-second head start through the intersection before drivers get a green light to proceed straight or turn, reducing the potential for turning conflicts that can result in serious injury or even death. “Every person who has almost right- or left-hooked me here is the reason the LBI exists,” he said.

Petru Sofio, an Arlington High School student, says he knows the phasing of every traffic signal in in Cambridge and Somerville as well as his hometown – and maybe in Belmont. (Photo: Jan Devereux)

The chance of being left-hooked by cars turning left onto Beech from Massachusetts Avenue southbound also has been reduced by another subtle change to the signal phasing. A “lagging” or “reverse” left-turn arrow now comes at the end of the green cycle instead of at the start. The change is crucial in giving northbound cyclists longer to clear the intersection without conflicts with southbound drivers turning left across their path. The length of the cycle for movements in all directions was reduced to 105 seconds from 120 seconds, so there is less waiting overall. Once a planned video camera is installed facing Beech, the signals will be able to self-adjust so the light on Massachusetts Avenue remains green when there are no cars waiting to turn onto it from Beech. A longer green cycle will reduce delays for MBTA buses using Massachusetts Avenue, an important benefit for transit users.

Petru takes characteristically modest pride in the role he played in advancing these changes. He bikes Massachusetts Avenue regularly between Cambridge and Arlington, and is acutely aware of its dangers. As we stood on the corner, we watched many drivers turn right on red despite signs forbidding it, while quite a few others made illegal U-turns on Massachusetts Avenue ignoring other signs. The rule of thumb is that 30 percent of drivers will ignore a prohibition on turning right on red, Petru said. While most drivers we observed did wait for a green to turn, several didn’t yield to pedestrians crossing Beech and a few cut off cyclists coming up behind them. There was a fair amount of honking at drivers who did yield. A sign warning “Turning vehicles yield to pedestrians and bikes” has been installed since our visit. The possible addition of a red turn arrow is under consideration.

While he thinks “quick build” bike lane changes have reduced some risks, Petru is looking forward to the full reconstruction planned with the MassAve4 project set to start in 2024. That work may not be complete until 2026 or so, however. Petru will be in college by then – locally, he hopes. He said he loves Cambridge and wants to stick around to see the Cycling Safety Ordinance fully implemented.

I hope he sticks around, too, and continues his highly effective advocacy. I wouldn’t be surprised if one day Petru leads the city’s or the state’s transportation department. I hope I’m around to see where his talent takes him – I might not have to wait long, given the head start he has on climbing the learning curve.