Crowd control barrier

Crowd control barriers (also referred to as crowd control barricades, with some versions called a French barrier or bike rack in the USA, and mills barriers in Hong Kong), are commonly used at many public events. They are frequently visible at sporting events, parades, political rallies, demonstrations, and outdoor festivals. Event organizers, venue managers, and security personnel use barricades as part of their crowd management planning.

Crowd control barriers act as a physical and psychological barrier, used to demarcate "no access" zones, and to designate space for lines. They are also used by riot police to control large gatherings.

Crowd control barricades are most commonly made of steel, although lighter-weight plastic variations are sometimes used. Barriers are most effective when they interlock, being attached to each other in a line via hooks at the side of each barricade. When barricades are interlocked, security personnel can create impenetrable lines, because such lines of barriers cannot easily be toppled over.

The French photographer Nadar has been credited the invention of the crowd control barrier. On his visit to Brussels with the balloon Géant, on September 26, 1864, Nadar erected mobile barriers to keep the crowd at a safe distance. Up to this day, crowd control barriers are known in both Belgian Dutch and Belgian French as Nadar barriers.

In the mid-to-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 about the same height. The horizontal bar consists of a heavy duty plank about 4.2 metres (14 ft) long with printed on it in large letters: Police Line - Do Not Cross. Beginning in the 1980s, steel barriers gradually took the place of wooden sawhorses at many events, including major holiday parades in New York City.

Interlocking steel barriers were patented in France in 1951. The original "Samia" barrier was developed to meet the need to maintain safety and order during France's social upheaval of the 1950s. This type of barricade soon became adopted for crowd control in other European countries, and eventually, the United States. Samia eventually went out of business, but many variations on its original barrier evolved over the years.

Barriers became an increasingly common sight, and without much fanfare, blended into the popular culture. Americans soon became accustomed to barriers being part of the background at important events. One of the earliest and most famous examples was the use of barriers at John F. Kennedy International Airport in New York City to control the hysterical crowds which greeted The Beatles' arrival in the U.S. in 1964. Steel crowd control barricades have been a common sight at the Olympic Games since the 1980s.

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