Bollard

Merwede-Canal, Utrecht, Netherlands features bollards made from cannons.

In the maritime contexts in which the term originates, a bollard is either a wooden or iron post found as a deck-fitting on a ship or boat, and used to secure ropes for towing, mooring and other purposes; or its counterpart on land, a short wooden, iron, or stone post on a quayside to which craft can be moored. The Sailor's Word-Book of 1867 defines a bollard in a more specific context as "a thick piece of wood on the head of a whale-boat, round which the harpooner gives the line a turn, in order to veer it steadily, and check the animal's velocity".[1][6] Bollards on ships, when arranged in pairs, may also be referred to as "bitts".[7][8]

A London street bollard in The City

Bollards can be used either to control traffic intake size by limiting movements, or to control traffic speed by narrowing the available space. Israel's Transportation Research Institute found that putting bollards at highway exits to control traffic also reduced accidents.[9]

Permanent bollards can be used for traffic-control or guarding against vehicle-ramming attacks.[10] 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.[11]

Bollards can be temporary and portable, such as this traffic control bollard separating the road from the worksite.

1980s traffic bollard in Prague, Czechia

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).[12]

Internally illuminated traffic bollards direct vehicles to the appropriate side of an island in the United Kingdom.

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:[13][14]

Internally illuminated traffic bollards have been in existence 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.[1] An illuminated bollard has a recessed base light unit in the foundation to illuminate the traffic bollard from all angles.[15] The main components are housed below the road or pedestrian surface (typically a concrete surface). Therefore, if a vehicle strikes the traffic bollard, the units 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 to no damage to the unit.[16]

Reflective bollards may also be used; they need no power or maintenance, and can be built to recover to their normal position after being struck.[17]

A bell bollard is especially useful to deflect heavy vehicles.

A bell bollard is a style of bollard designed to deflect vehicle tires. The wheel mounts the lower part of the bollard and is deflected by its increasing slope. Such bollards are effective against heavy goods vehicles that may damage or destroy conventional bollards or other types of street furniture.[18]

Manually retractable bollards (lowered by a key mechanism) are found useful in some cases because they require less infrastructure.[19]

The term "robotic bollards" has been applied to traffic barricades capable of moving themselves into position on a roadway.[20]

Self-righting or self-recovering bollards can take a nudge from a vehicle and return to the upright position without causing damage to the bollard or vehicle. They are popular in car park buildings and other areas of high vehicle usage.[21]

Flexible bollards are bollards designed to bend when struck by vehicles. They are typically made from synthetic plastic or rubber that is stiff on its own, but pliable under the weight of a car or truck. When struck, flexible bollards give way to some extent, reducing damage to vehicles and surrounding surfaces, and return to their original, upright position. Some flexible bollards do not provide physical protection from vehicles; rather they offer clear visual guidance for drivers. Other flexible bollards have been designed to provide physical protection as well as reduced damage by incorporating strong elastic materials. These can be all plastic or plastic/steel hybrids but combine varying degrees of stopping power and flexibility.[22][23][24][25]

Security bollard in front of a shop doorway, placed to deter ram-raiders

Concrete planters provide protection similar to that of bollards. Washington, DC

Bollards are used by government agencies and private businesses to protect buildings, public spaces, and the people in them from car ramming attacks.[26]

These bollards protect utilities, electronics, machinery, buildings, or pedestrians from accidental or intentional collisions with vehicles. As collisions also cause damage to vehicles, operators, or the bollards themselves, new bollards have been developed that absorb some of the impact energy, lessening the violence of the collision. Some are made of forgiving plastics while others are made of steel but fitted with an elastomer to absorb the impact energy.[27]

Bollards are widely used to contribute to safety and security. The American Bar Association (ABA) states that bollards are used to contribute to homeland security.[28] The American National Institute of Building Sciences site—the Whole Building Design Guide (WBDG)—recommends in its Design Guidance that open spaces surrounding and contiguous to buildings be included as integral parts of a security design.[29]

There are two main kinds of security-related bollard:

• Non-crash-resistant bollards.
• Crash- and attack-resistant bollards used to protect places at risk of being attacked.[30]

According to the National Institute of Building Sciences, non-crash-resistant bollards are "perceived impediments to access" and address the actions of two groups:

• Law-abiding persons who comply with civil prescriptions of behavior as defined by the manner in which bollards are put to use;
• Potentially threatening and disruptive persons for whom bollard applications are proscriptive by announcing their behavior is anticipated, and that additional levels of security await them.[31]

High security bollards are impact-tested in accordance with one or more of three major crash test ratings for vehicle barriers. These are PAS 68 (UK),[32] IWA-14 (International) and ASTM (US).[33][34]

Bollard sleeves in various alloys or finishes are designed to cover security bollards to enhance their visual attractiveness.[35]

U-shaped bollards are typically used for the protection of equipment and are common in areas that need coverage over a wider area than of a normal bollard, such as fuel stations and bike lanes.[36]

Bollards have become common use for reserving parking spots from unauthorized vehicles. Parking bollards are typically situated in the centre of a parking bay as a physical obstruction. They then fold either manually or automatically to admit authorized users. These bollards are often used in smaller parking lots such as visitor parking or corporate parking lots, as an alternative to boom gates.

The National Clearinghouse for Educational Facilities (NCEF), managed by the National Institute of Building Sciences (NIBS), cited three dozen applications of bollards.[37][38]