Just as the morning commute was getting underway on July 11, more than 100 people walked off the curb at the corner of Fenway and Brookline Avenue in Boston's Longwood / Fenway neighborhood, and, linking arms, formed a human wall inside the painted lines marking a new bike lane.

The protest was organized by the Boston Cyclists Union, and on a recent evening, Executive Director Becca Woflson showed me what her group sees as a potentially fatal flaw in the new bike lane.

"You’ll see there’s a fairly wide nice bike lane and a painted buffer," said Wolfson, "but there's nothing to physically separate the cars from the bike lane."

The Cyclists Union has been pushing for physical barriers between traffic and bicyclists, especially on the big, multi-lane roads where the most serious and deadly crashes occur.

And this is one of those hotspots. In February, 69-year-old Brookline children’s librarian Paula Sharaga was hit by a truck and killed while crossing the Fenway parkway.

After Sharaga's death, activists doubled down on their demands for physical separation for bike lanes, with some success.

Around the corner, on Brookline Avenue, the city of Boston has buffeted the bicycle lane with flexible white plastic posts. Other surrounding cities have also been increasingly employing similar physical separations for at least some bike lanes, and the Massachusetts Department of Transportation has been adopting and implementing guidelines for when physical barriers are appropriate.

But the agency that oversees Fenway — the state’s Department of Conservation and Recreation (DCR) — has refused to consider adopting similar measures, Wolfson said.

"The response I got was they don’t believe in that kind of separation, because they feel it gives a false sense of security," Wolfson said. "I would say, in that spirit, crosswalks provide a false sense of security — should we take all crosswalks away?"

And according to Wolfson and other safe streets advocates, the new bike lane on Fenway isn't an isolated case.

"DCR has made it very clear they're refusing to put in any type of delineator on this project or on any of the roads that they manage throughout the city and the state," said Wolfson.

DCR’s main job is to oversee Massachusetts’ parks, but it also controls dozens of miles of roads that run along them, including Storrow Drive, Jamaicaway, the Riverway and Revere Beach Parkway.

They’re iconic roadways — but also some of the area's widest, fastest and most dangerous.

A WGBH News analysis found that of about 5,000 serious crashes involving bicyclists or pedestrians between 2015 and 2019, nearly 900 occurred on or within 100 feet of DCR roadways – including at least 20 crashes on or near Fenway in less than four years.

A few weeks before Sharaga was killed crossing Fenway, Marilyn Wentworth of West Roxbury was hit and killed walking across Centre Street — another road overseen by DCR. Last November, Cambridge student Meng Jin was hit and killed while bicycling along Monsiegnor O’Brien Highway, another DCR road that still has no bike lane.

Safe streets groups say it's no coincidence that many of the roads lining the area's parks and green spaces are also among the region's most dangerous roadways.

"A lot of this infrastructure was built in the 1950s and '60s and '70s, when there was a clear cultural interest in motor vehicles and a perception that that was our future," said Stacy Thompson, executive director of the Livable Streets Alliance.

Thompson says a lot of region's parkways were designed at time when cars were king.

"So these roadways were overbuilt to accommodate vehicles," Thompson said, "and the result is now really unsafe infrastructure."

DCR Commissioner Leo Roy declined to be interviewed for this story, but DCR did send an email from spokesperson Troy Wall in response to a number of our questions.

Wall said the agency takes bike infrastructure seriously — and notes that DCR has incorporated bicycle-specific safety improvements into many of its road improvement projects. Wall didn't say whether DCR has adopted any specific guidelines or policies dictating when, or if, a protected bike lane should be used.

For advocates like the Cyclists Union's Becca Wolfson, these questions aren't just about abstract policy.

"People are being injured, people are being hurt. Crashes are occurring almost every other day," Wolfson said. "This is a crisis, and we should be addressing this."

Wolfson, Thompson and other safe streets advocates say they want to work with DCR, not against the agency, and they are the first to say that DCR is under-funded and under-staffed.

But that might be all the more reason, they say, the state’s parks department should concentrate on parks, not roads — especially if those roads aren’t getting safer.