Bollards are part of perimeter protection which guard people as well as building and property functions and services. They are used to guard against vehicles that are not authorized to approach or penetrate these areas.
The United States Department of State uses these type of anti-ram barriers around its embassies. They are also used in government facilities and military installations. There are commercial and industrial applications as well.
New York City has installed heavy concrete barriers, or bollards, to protect against vehicle attacks in areas around where large crowds are active.
Earlier this year an article from CBS Evening News told: “How U.S. authorities are trying to keep pedestrians safe from vehicle attacks”. Read the article and see the image at http://www.cbsnews.com/news/how-u-s-authorities-are-trying-to-keep-pedestrians-safe-from-vehicle-attacks/
Vehicles were used in two new terrorist attacks in London and Paris just yesterday.