Bollards and k-rail (concrete highway barriers) meant to keep out bomb-laden vehicles are giving way to barricades designed to blend with the appearance of streets and buildings.

Far from reassuring those they are meant to protect, fortifications of any design create “a climate of fear,” says architect Michael Sorkin, director of the graduate design program at City College of New York. “It’s creating a kind of culture of paranoia.”

The goal now is to make public places safe but not scary:

• In Chicago, low walls wide enough to sit on surround flower beds and protect the 100-story John Hancock Building. They replaced temporary barricades.
• In Seattle, a large lily pond outside the 2-year-old federal courthouse acts as a moat.
• At the state Capitol in Sacramento, bollards linked by steel cables are being installed around the building, but they will be hidden inside hedges.

Obvious blockades, such as the highway barriers and concrete planters that followed 9/11, create unfriendly spaces that are difficult to navigate and where people don’t want to linger, says Mark Rios, a Los Angeles landscape architect who is writing a guide for government agencies on good security design.

Even harder than installing unobtrusive security is knowing when to stop. Ring one building with a moat, a wall or a line of steel posts, and “the next building becomes the target,” Levy says. “At some point, you have to ask yourself what makes sense. Do you put perimeter security around every building in a city?”