Putting Protective Barriers in Front of Bike Paths Isn't So Simple

After Tuesday's deadly attack in lower Manhattan, pundits and politicians are calling for the installation of bollards to protect more public spaces — including the spot where the killer entered the bike path with his truck. Doing so, however, isn't as easy as you might think.

Bruce Schaller is the former deputy for traffic and planning with the city's Department of Transportation, and he'd like to put the problem in perspective for you.

"There are an untold number of locations in New York City or any other major city," says Schaller, "where there are lots of pedestrians and one could make a high profile attack. Can you put bollards to protect all of them? You just...it can't be done."

All right. Let's narrow the focus to Hudson River Park, where the terrorist attack occurred. It stretches four miles from Battery Park to 59th Street, and has thirty-one points where vehicles cross the bike and pedestrian paths and could start running people over.

Sayfullo Saipov, the suspect in Tuesday's attack, began his rampage at Houston Street. There are bollards in the bike path but they're flexible and flimsy — unlike the formidable bollards at 57th and 59th Streets. Those were added to the path in 2006, after a drunk driver entered the path at that spot and killed a 22-year-old cyclist.

But here's where Schaller raises his hand and complicates the notion of car-proofing the entire park.

"If you then put bollards into that situation," he says, "you are increasing the risks involved. As people move through that, they may run into each other. There's a real trade-off to that. And you could say, 'Everyone should slow down.' But that's New York. And people are actually trying to get exercise."

The Department of Transportation now says it will use cement blocks to narrow access to bike and walking paths at all thirty-one vehicular crossings in Hudson River Park.