New Yorkers turn to the Hudson River Greenway each day for the peace of pedaling free of car traffic. On Tuesday, America’s busiest bike path became a scene of terror.

“This is a tough day for all New Yorkers — and tough for everyone in the United States and around the world who regularly bikes and walks on city streets,” said Caroline Samponaro, with the New York advocacy group Transportation Alternatives.

“There exists already a baseline sense of vulnerability. Now that feeling is heightened,” she said.

Police say 29-year-old Sayfullo Saipov plowed a rented Home Depot truck into people using the bike path Tuesday afternoon, in what they describe as a deliberate act of terrorism. Eight people were killed and 12 injured.

The attack immediately spurred calls on Twitter for local governments to add safety measures to prevent vehicles from encroaching on spaces used by pedestrians and bicyclists. But many riders said the attack didn’t discourage them from returning to the same bike path where the carnage occurred.

A day after the attack more people were out biking, according to Transportation Alternatives, which promotes bicycling, walking and the use of public transit, and has 100,000 public supporters.  The sentiment was also shared in other cities across the U.S., where biking has become a popular mode of getting around.

“Are we going to be brave and keep going about our lives and not let the terrorists win?” said Tamara Evans, an avid rider in Washington, D.C., who leads advocacy efforts at the Washington Area Bicyclist Association. “This is America in the age of terror…But it won’t keep me from riding my bike to work.”

In New York,  advocates say they hope the incident leads to a greater sense of urgency to implement protections in areas such as the Hudson River Greenway, where thousands of people bike and walk, and where the city has long known its flaws. Advocates there have sought the installation of posts known as bollards and other measures to prevent cars from entering the path.

“With the very real threats that New York City faces, we must restrict vehicle access to New York City’s most vulnerable areas, such as Lower Manhattan and Midtown,” Samponaro said.

More widely, groups in New York and Washington say cities should begin regulating and limiting trucks and vehicle access to the most crowded areas, not only for safety and security, but traffic control.

Experts and advocates acknowledge that it would be difficult to retrofit every street to prevent similar attacks. But they say small steps from adding metal bollards and concrete barriers can go a long way to provide greater separation between cyclists and drivers.

Brian McEntee, who writes the Gear Prudence bike advice column for Washington City Paper, said bicyclists shouldn’t be more worried than anyone else about being a targeted group or especially susceptible.

But Tuesday’s incident is especially disturbing, he said.

“Because people who bicycle, especially in a city, develop a much greater sense of the potentially destructive powers of cars than people who don’t. It’s visceral,” McEntee said.

“There’s no metal or glass between you and your surroundings and no seatbelts or airbags to give an extra sense of safety should a collision occur,” he said. “Awareness and acknowledgement of this, I think, makes bicyclists more sensitive to the kind of damage, intentionally done or unintentionally done, that cars can cause.”

Still with a greater spirit of solidarity for those killed on the bike path, New Yorkers are determined to “keep on riding,” Samponaro said.

“We will keep riding,” she said.