The intersection of Massachusetts Avenue and Beacon Street is considered Boston’s most dangerous for cyclists, a treacherous Back Bay gantlet of heavy traffic, constant noise, and a rush to beat the stoplight.
The death of a cyclist Friday morning struck there by a tractor-trailer became the latest in a string of accidents at the busy intersection as bicycling becomes increasingly popular in the city’s crowded, chaotic streets.
“I don’t know what it is about this intersection, but people are constantly getting hit — pedestrians, bikers — some type of accident,” said Aymen Rajeh, who owns nearby Quality Mart.
Authorities located the truck out of state Friday night and questioned the driver, a Boston Police Department spokesman said. No charges had been filed, but the investigation was continuing.
The victim, in her 30s, was pronounced dead at Massachusetts General Hospital. She had not been identified Friday, pending notification of family.
The collision occurred around 7 a.m. as a long flatbed truck loaded with steel made a right turn from Massachusetts Avenue onto Beacon Street, police said. The truck did not stop, but police did not immediately classify the collision as a hit-and-run.
Mayor Martin J. Walsh said the death shows the need to improve cycling safety. “It’s a tragedy anytime you hear of anyone dying, but particularly when you hear about bikes or pedestrians on the streets,” Walsh said. “We are working on a full plan for the city.”
Fourteen accidents involving cyclists were recorded at the intersection between 2009 and 2012 — more than any other spot in the city. As police combed the scene for evidence Friday morning, people at the intersection decried what they called a perpetually dangerous place.
“That’s an intersection that I ride through regularly, and it’s definitely one where I have my guard up,” said Lauren LeClaire, a spokeswoman for the Massachusetts Bicycle Coalition. She commutes by bicycle from Somerville to the Financial District.
Zach Cloyd, who lives next to the collision scene, said he has stopped biking home from work because the area is treacherous. “That exact corner, waiting at that corner, I’ve had someone almost hit me as they were turning right,” he said.
The intersection can be a blur: Massachusetts Avenue has two lanes in each direction, while Beacon, a one-way street, has two lanes. There are bike lanes, crosswalks, a bus stop, a Hubway station for bicycles, and curbside parking.
The next-most-dangerous crossing for cyclists — nearby at Massachusetts Avenue and Commonwealth Avenue westbound — recorded 12 accidents from 2009 to 2012, according to the most recent data available.
Since then, the number of cyclists in Boston has soared, bike lanes offer only limited protection, and cyclists say that many motorists remain hostile to them or indifferent to their safety.
“You do see a higher crash rate when you have more cyclists on the road,” said LeClaire. “But you have greater awareness that there are more bikes out there.”
Alex Epstein, an engineer at the Volpe Center, a federal transportation research lab in Cambridge, estimated that the number of cyclists in Boston has doubled in the last five to 10 years.
To accommodate them, the city has installed nearly 100 miles of bike lanes, including buffered lanes on some streets that separate cyclists from motorized traffic, said Gina Fiandaca, the city’s transportation commissioner.
The death Friday, Epstein said, might have been prevented if the truck had been outfitted with features as simple as a $50 blind-side mirror and “side guards” that protect pedestrians and cyclists from being run over by a truck’s rear wheels.
Images of the truck involved in the collision do not appear to show side guards or that mirror, Epstein said. The guards, which hang from the bottom of the trailer, act as a wall to prevent people from being trapped under a moving truck and struck by its rear wheels.
Last year, Boston approved an ordinance requiring that all large trucks owned or contracted by the city have side guards. The city also requires additional mirrors to improve visibility.
“Every one of these tragedies has some lessons,” Epstein said. “Truck safety is a big issue we should pay attention to. A large fraction of pedestrians and cyclists killed in the Boston area are killed by trucks. This just adds to that sobering trend.”
Valerie A. Yarashus, a Boston lawyer who is on a US panel to promote side guards, said the added protection is “critically important in urban areas.”
Yarashus represents the families of two cyclists killed by trucks in Boston: Christopher Weigl, a Boston University student who was struck by a tractor-trailer in 2012 in Allston, and Owen McGrory, who died in 2014 after being hit by a garbage truck in Charlestown.
Peter Stidman, executive director of the Boston Cyclists Union, said trucks and other large vehicles pose unique dangers for cyclists, particularly when the vehicles are turning. Not only does the sheer size of a large vehicle increase the odds that a collision will seriously injure a cyclist, but drivers of large vehicles often cannot see their surroundings.
Large vehicles also need to make wider turns that can be deceiving.
“A tractor-trailer may appear to be going left, but they are actually making a right turn,” Stidman said. “It’s really difficult for you to judge what they’re doing . . . . Even if they know to look over their shoulder when they take a right turn, they really can’t see you.
“A key thing I tell all cyclists is: Be extremely aware when passing a large vehicle on the right,” he added.
Stefanie Seskin, deputy director of the National Complete Streets Coalition in Washington, will begin Aug. 17. As part of her duties, Seskin will oversee Boston Bikes, which includes the Hubway bike-share program.
“Boston is an active city, and we are continuing to invest in our pedestrian and bike infrastructure, encouraging residents to think creatively about how they get from point A to point B,” Walsh said when he announced the appointment.
Steve Annear and Andrew Ryan of the Globe staff contributed to this report. Brian MacQuarrie can be reached at brian.macquarrie @globe.com; Matt Rocheleau at matthew.rocheleau
@globe.com. Follow him on Twitter @mrochele.