Faulty reasoning signals

• Halo Effect - 30.7%
• Appeal to Emotion - 11.9%
• Negativity Bias - 10.3%

Article text

Louisa Gag was cycling early Thursday when she was fatally struck by a vehicle on Tremont Street. Submitted Photo

Louisa Gag was an enthusiastic cyclist, regularly riding the winding streets of Boston. Her passion extended to her professional life, where she worked in City Hall as a bike-share and transportation planner to improve safety and accessibility on those very same roadways.

On Thursday morning, Gag was riding near Roxbury Crossing, an area known for its heavy and high-speed traffic, when she was fatally struck by the driver of a truck on Tremont Street, authorities said.

The crash sent shockwaves through the cycling community, where advocates recalled the Roslindale resident’s effusive joy and wide-ranging impact. And it also hit close to home in City Hall, where Gag had been an intern for Mayor Michelle Wu when she was a city councilor.

“Our hearts are with her family, friends, colleagues, and all whose lives she touched,” Wu said in a statement. “I am absolutely devastated by this unfathomable loss for our community and our city.”

Gag began working for Wu as a policy fellow when the latter was a city councilor and quickly became a “trusted colleague and partner,” the mayor recalled in her statement. She led programs and improvements that “made our streets safer, our communities stronger, and our residents’ daily lives better,” Wu said. “Her legacy will endure in the work she advanced across the city, and in the commitment of her colleagues, friends, and fellow advocates to carry it forward.”

The crash occurred a short distance from Southwest Corridor Park. The driver stopped afterward, officials said.

The circumstances of Thursday’s crash were not immediately clear. Suffolk District Attorney Kevin Hayden said his office is investigating along with Boston police.

“The investigation of Louisa’s tragic death is underway and will be thorough and careful,” Hayden said.

The area of the crash has been a source of concern and frustration for cycling safety advocates in recent years.

“We all know how dangerous Tremont Street is,” said Tiffany Cogell, interim executive director of the Boston Cyclists Union, which has an office near the scene. She and others expressed both grief and anger.

“Louisa is such a loved and tight member of our community. For this to happen where it did just adds insult to injury.”

The tragedy also occurred during a time when some transit advocates have criticized Wu for stalling a number of street improvement projects they said would improve public safety. One such area that’s been targeted for improvement is the busy intersection at Roxbury Crossing, a few blocks from the crash scene.

Wu has said street safety remains a priority for her administration, and emphasized that work on many such infrastructure projects is ongoing.

In 2025, there were 256 crashes in Boston that resulted in a cyclist being injured, according to the city’s “Vision Zero” database, which relies on data from Boston Emergency Medical Services. No fatalities were reported. Data on crashes involving cyclists in the city this year was not available.

The cyclists union on Wednesday renewed its call for Wu to “unpause the projects that will provide needed safety to prevent these deaths, which don’t have to happen,” Cogell said.

Meanwhile, Boston City Councilor Sharon Durkan, whose district includes Roxbury Crossing and who also chairs the chamber’s planning, development, and transportation committee, demanded the city fast-track safety infrastructure in the wake of Gag’s death Thursday.

“We cannot stand by and watch more fatalities happen on our streets,” Durkan said.

Gag was raised by civically engaged parents and was a graduate of Boston Latin School, friends and family said. Before joining the city in 2022, she worked for LivableStreets Alliance, a Boston-based nonprofit that pushes for increased safety, equity, and affordability, according to the group’s website.

Stacy Thompson hired her, at a time when the organization was small. They grew with it together and became fast friends, she said. Her spark was immediately apparent, Thompson said.

Gag was the original author of the nonprofit’s progress reports on “Vision Zero,” a global movement that Boston committed to more than a decade ago, she said. The strategy is aimed at eliminating traffic fatalities and severe injuries by focusing on safe mobility for all road users. She was responsible for listing the names of people who had died as a result of crashes in the city, Thompson said through tears.

“It is unimaginably hard to add her name to that list,” she said.

Gag left advocacy to work at City Hall because she “believed fundamentally in the civic duty of the city,” she said. She desired to make real change — “and she did,” Thompson added. A big part of her work centered around expanding the bike-share program, Bluebikes, and encouraging more people to bike.

And she was effective everywhere she went, capable of gaining trust among advocates, community members, and people in positions of power, Thompson said. People could tell that she cared, she said.

“It wasn’t just a job for her,” said Thompson, who added that Gag’s contributions “cannot be summed up in one single accomplishment.”

“There are streets you cross that are safer because of Louisa,” she said. “She is in the fabric of the city. The only thing we can do, which she would want us to do, is to move forward and to move faster.”

Galen Mook, executive director of MassBike, collaborated with Gag for more than a decade on efforts to improve the safety of roadways in Boston, calling her a “champion of the work.” She showed up to everything — from celebrations to hard conversations — and always did so “with a smile,” he added.

“She comes from a vision and a mission of generations worth of change in the city,” he said. “This is a reaffirmation of the need to continue the work and redouble the efforts to push it forward.”

“Because this is a preventable tragedy,” he added.

Another bike safety advocate and friend of hers, Peter Cheung, said the community plans on holding a memorial for Gag after family and community members have a chance to grieve. For years, he has organized “ghost bike” installations at the scene of cyclist fatalities to remember those killed.

But “this is as close as it has hit to home, for everyone,” Cheung said.

Bryan Hecht can be reached at bryan.hecht@globe.com . Follow him on Instagram @bhechtjournalism . Shannon Larson can be reached at shannon.larson@globe.com . Follow her @shannonlarson98 . Niki Griswold can be reached at niki.griswold@globe.com . Follow her @nikigriswold .