Crowd control barrier

A crowd control barrier (with some versions called a French barrier in the USA), is used to direct the flow of large numbers of pedestrian traffic. Crowd control barriers are often erected to ensure the safety of crowds and to ensure an orderly queue is established such as for concerts and sporting matches.

Crowd control barriers are also used by riot police to control large gatherings, and stop them from escalating out of control. In the late 20th century a common version was made of wood in the shape of a sawhorse. The legs are similar but rather heavy duty facsimiles of the hobby sawhorse-version, and of about the same height. The horizontal bar consists of a heavy duty plank of about 4.2 meters (14 feet) long with printed on it in large letters: Police Line - Do Not Cross. The wooden sawhorses, used as barriers, are slowly being replaced. In New York, for example, in 2007 only about 3,200 wooden sawhorses (14 feet long and $60 each) remain. They are being replaced by an aluminium version, called a French barrier (in the USA) of which New York now (2007) uses about 12,000 (2 meters (7 feet) long and $70 each). Other cities like Chicago and Philadelphia also use both types.

Main advantages of the aluminium barriers:
 * they can be interlocked and thus be a more effective barrier against surging crowds.
 * one piece (the wooden sawhorse type is three pieces) and light and thus easy to transport.