Traffic bollard

Traffic bollards are short, pillar-like objects used to obstruct roads for traffic control and pedestrian safety. Bollards work by limiting movements and controlling traffic speed by narrowing the available space.

Permanent bollards can be used for traffic control or guarding against vehicle-ramming attacks. They may be mounted near enough to each other that they block ordinary cars/trucks, for instance, but spaced widely enough to permit special-purpose vehicles, bicycles, and pedestrians to pass through. Bollards may also be used to enclose car-free zones. Bollards and other street furniture can also be used to control overspill parking onto sidewalks and verges.

The term is probably related to bole, meaning a tree trunk. The earliest citation given by the Oxford English Dictionary (referring to a maritime bollard) dates from 1844, although an account describing bollards as "huge posts" in a shipyard is also known from 1817. The earliest citation given by the OED referring specifically to a traffic bollard dates from 1925.

Wooden posts were used for basic traffic management from at least the second half of the 17th century. One early well-documented case is that of the "postes and rales in ye King's highway for ye (safety) of all foot passengers" erected in 1671 in the High Street of Old Brentford, Middlesex (part of the London–Bath road). Another is that of "two oak-posts" set up next to the medieval Eleanor cross at Waltham Cross, Hertfordshire, in 1721, at the expense of the Society of Antiquaries of London, "to secure Waltham Cross from injury by Carriages".

Historically, bollards were sometimes created from old cannon, buried muzzle-downwards in the ground.

Traffic bollards are used to highlight traffic islands. They are primarily used at intersections within the splitter islands (a raised or painted area on the approach of a roundabout used to separate entering from exiting traffic, deflect and slow entering traffic, and provide a stopping place for pedestrians crossing the road in two stages).

Illuminated bollards are also used to supplement street signs and street lighting to provide a visual cue to approaching drivers that an obstacle exists ahead during hours of darkness and during periods of low visibility:

Internally illuminated traffic bollards have been used throughout the United Kingdom and Ireland since the 1930s, although the term "bollard" only seems to have been in common use since the late 1940s. An illuminated bollard has a recessed base light unit in the foundation to illuminate the traffic bollard from all angles. The main components are housed below the road or pedestrian surface (typically a concrete surface) so that if a vehicle strikes the traffic bollard the parts below the surface are not damaged. In addition, most new modern traffic bollards installed along UK roadways today are made of materials that make them completely collapsible. When struck by a vehicle at low or high speed, the traffic bollard shell reverts to its original position with minimal or no damage to the unit.