Bollards, or How Cities Are Protecting Their Public Spaces From Terrorism

bollards. terrorism — Bollards and other structures are becoming an increasingly important part of defensive urban design. Christopher Lee/Getty Images

After the British defeated Napoleon's navy in the Battle of Trafalgar in 1805, they stripped the French ships of their cannon, but found that their size wasn't a good fit with British ships. So instead, as London guidebook author Simon Leyland recounts, they implanted the cannons vertically in various locations along London's streets, where they served as decorations to remind passers-by of the historic victory.

Two centuries later, bollards, as such posts are known, have again become a common design feature in cities in the U.S. and elsewhere. But their main purpose isn't decorative. Instead, today's bollards — often made of strong, resilient steel pipe — are intended to protect urban dwellers and visitors from rampaging vehicles that have been turned into weapons by drunk drivers or, worse yet, terrorists bent on inflicting carnage.

Bollards already have shown their value in New York City. In May, after a car drove the wrong way up a one-way street and slammed into dozens of pedestrians, killing one, bollards prevented the vehicle from inflicting even more injuries and fatalities, according to USA Today. More recently, after a truck veered into a bike lane killing eight people and injuring 12 in what federal authorities say was an act of terrorism, city officials began installing bollards to protect the route. U.S. Sen. Kirsten Gillibrand, D-NY, has introduced legislation calling for the federal government to provide $50 million in grants to cities to install more of the protective devices.

Bollards are part of the growing trend toward defensive design in U.S. cities and elsewhere in the world. Increasingly, outdoor public spaces are being redesigned to include a variety of subtle features — from sight lines to the design of park benches — that are intended to protect users from terrorism, crime and other violent threats, and sometimes also to thwart behavior that's been deemed undesirable.

Such defensive design measures vary according to what the city is hoping to prevent, explains Randy Atlas. He's a Florida-based architect with a doctorate in criminology who is both a Fellow of the American Institute of Architects and a Certified Protection Professional, a distinction conferred by ASIS International, a security industry organization. "How do you design public spaces to resist acts of incivility, criminal acts and potential acts of terror?" he says. "There's a different answer for each one."

At one end of the spectrum, a city might use design to keep a public square from being taken over by skateboarders or graffiti taggers, or turned into a campsite for homeless people. Some outdoor places, for example, now have outdoor benches with armrests, which make it difficult for homeless people to sleep on them, as well as knobs and other impediments attached to surfaces to prevent them from being used by skateboarders to do stunts.

On the next level, deterring crime such as assaults and robberies in a public space requires more extensive measures, Atlas says. Landscaping and structures can be crafted to allow good lines of sight for police patrols and video surveillance, so that perpetrators who aren't deterred can be spotted and caught.

But terrorism, the most extreme threat, is more difficult to protect against, because the attackers, unlike ordinary criminals, aren't motivated by the desire to get away to enjoy the fruits of their labor. "Terrorists want to take as many people as possible with them," Atlas says. "They don't expect to live."

Creating Physical Barriers

That's where physical barriers such as bollards come in. Rob Reiter, chief security consultant for Calpipe Security Bollards, a California-based manufacturer, says the devices aren't as imposing or obtrusive as fences or other fortifications, and instead allow people to enter a space freely while keeping them safely separated from vehicles.

Reiter said that the concept of bollards hasn't changed that much over the years, except for the advent of retractable remote-control models that can be raised up or down by tapping a smartphone app. They're generally sturdy pieces of steel pipe, with the heaviest models for terrorism protection measuring 10 to 12 inches (25 to 30 centimeters) in diameter, which are embedded in the ground for stability.

According to Reiter, bollards generally are hollow rather than solid, because it allows them to be flexible enough to bend and absorb the force of a vehicle. "With a round pipe, the impact side stretches out the front, and the back side compresses," he says. "The front stretches by 5 percent and snaps back. Like a tree, it's better to sway with the wind than break off."

Increasingly, bollards are subjected to rigorous crash tests to determine their capabilities. "You want to know, will this stop a terrorist in a 15,000-pound (6,803-kilogram) truck going 50 miles (80 kilometers) an hour?" Reiter explained. "You want to know that if it's installed this way, will it stop this vehicle?"

For a look at just how much force a typical bollard can withstand, check out this video from Calpipe:

In addition to protecting against terrorists, bollards also are a useful tool for creating urban environments in which pedestrians and cyclists can co-exist with cars and trucks, according to Caroline Samponaro, a deputy director at Transportation Alternatives, an organization that promotes walking and biking as transportation methods. "We need our public spaces in cities to be more pedestrian friendly," she said.