Wikipedia:
illuminated traffic bollard |
Internally illuminated traffic bollards (herein referred to as traffic bollard) have been in existence throughout the United Kingdom since the 1930’s. They are primarily used at modern roundabout intersections within the splitter islands (a raised or painted area on the approach of a modern roundabout used to separate entering from exiting traffic, deflect and slow entering traffic, and provide storage space for pedestrians crossing the road in two stages)[1]:and at the ends of pedestrian refuge islands, typically located at mid-block pedestrian crosswalks. They are 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[2][3]:(fog, rain, snow, haze, etc.) and that braking may be required.
A traffic bollard consists of three parts[4]: (1) a foundation used to house a recessed base light unit; (2) A base unit which houses lamps to illuminate the traffic bollard; (3) a shell which illuminates at all angles during periods of darkness and low visibility. Units one and two are housed below the surface of the improvement (typically a concrete surface). Therefore, if a vehicle strikes the traffic bollard, the units below the surface are not damaged.
Road agencies in the United States are beginning to experiment with modern traffic bollards. The first modern traffic bollard was installed at a modern roundabout intersection (State Road 89 and Willow Lake Road) in the City of Prescott, Arizona (see middle thumbnail photo at right). The traffic bollards at this intersection are very similar to devices found throughout the United Kingdom with the following exceptions:
1) The traffic bollard shell displays the MUTCD (Manual of Uniform Traffic Control Devices) “Keep Right” symbol (R4-7). In addition, the traffic bollard also has a yellow diamond below the keep right symbol instead of a yellow shield.
2) Unlike many existing traffic bollards found in the U.K., most new modern traffic bollards installed along roadways today are made of materials that make them completely collapsible. When struck by a vehicle at a low or high rate of speed, the traffic bollard shell reverts to its original position with minimal to no damage to the unit. The following link Striking a Bollard demonstrates this feature.
The following link Bollard in the Distance represents how an approaching driver views a traffic bollard at night. The video was taken at a modern roundabout intersection that was under construction at the time of filming.
References
- ^ U.S. Department of Transportation: "Roundabouts:An Informational Guide", FHWA-RD-00-067, 2000
- ^ "Road Traffic Signs and Internally Illuminated Bollards. Specification for Internally Illuminated Bollards", British Standards Institution, 1980
- ^ Philip Weber, Scott Ritchie: "Internationally Recognized Roundabout Signs", Paper for the Transportation Research Board National Roundabout Conference, 2005
- ^ Simmonsigns, Simbol Product Specifications, 2006
This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)
