Patent Application
20060028808
This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/592,656, Filed Jul. 30, 2004.
1.Field of the Invention
This invention relates to roadway lighting. In particular, this invention relates to highway barrier lighting systems utilizing Light Emitting Diodes (LEDs).
2. Description of Related Art
Conventional roadway lighting is accomplished with overhead light standards mounted to a structure (e.g. a crash barrier or other structure serving as a physical barrier). Conventional overhead luminaries are glary, and the light that is emitted is uncontrolled, resulting in light trespass. Light trespass is an issue when a viaduct or roadway passes over or near a populated area. Conventional overhead lighting systems provide relatively high light levels over a very large horizontal area including the shoulder. However, the edge or shoulder is not highlighted but rather visually blended into the roadway scene. The overhead and diffuse (multidirectional) nature of the conventional lighting does not enhance small target visibility. Small targets are visually lost under conventional roadway lighting.
In the field of roadway lighting, the desire to improve small target visibility has been frustrated by the use of conventional overhead lighting. Direct overhead illumination by unfocused (diffuse, propagating in all directions) light makes small objects/targets invisible. Previous unsuccessful attempts to address the issue of small target visibility include development of asymmetric overhead light sources.
A need remains in the art for an alternative strategy of lighting, which reduces light trespass into a populated or other light sensitive area, enhances small target visibility, and reduces energy consumption without compromising the safety of motorists/travelers.
An object of the present invention is to provide roadway lighting systems which reduce light trespass, enhance small target visibility, and reduce energy consumption without compromising the safety of motorists/travelers. This object is accomplished using an LED system for providing lighting for roadways, as well as viaducts, pathways, etc. The LED system provides a strategy to mitigate light trespass and light pollution, and highlight roadway edges when motorist/traveler guidance is critical.
The present roadway lighting system provides guidance to travelers, defines the edges of the roadway, illuminates animals or vehicles stopped on the shoulder, indicates on-ramp and off-ramp locations, and enhances safety of merging traffic. The LED lighting system illuminates with uni-directional lighting and thereby eliminates the problem of small target visibility.
The LED system provides the necessary illumination to enhance motorist guidance (beam illumination) and highlight disabled vehicles (field illumination).
Additionally, the low energy use and long lamp life of LED systems reduces maintenance and operating costs.
Apparatus for lighting a roadway according to the present invention comprises an elongated barrier unit which is placed along the side of the roadway, generally parallel to the roadway. The barrier unit forms a recessed area in its roadway-facing surface. Within the recessed are of the barrier is installed an LED lighting element having a plurality of LEDs fixed in an elongated formation, oriented in a generally vertical orientation. This results in the LED lighting element providing an approximately horizontal sheet of light along the barrier.
The barrier might be, for example, a continuous cast-in-place barrier, a discrete crash barrier, a snow fence, a tunnel wall, a guard rail, or a bollard.
The roadway could be, for example, a viaduct, a highway, an on-ramp or off-ramp, or the like.
The LED lighting element can be powered in a number of ways, including via a generator, a battery, a fuel cell, a photovoltaic system, or an electrical power supply.
Historically, roadways and highways are lighted using luminaries on tall poles located on the edge of the pavement. This LED system provides an alternative to tall poles by providing vertical or near vertical sheet illuminance on the shoulder, thus increasing small target visibility and highlighting any animals motorists stopped on the shoulder. Since the described LED luminaire lights the vertical or near vertical sides of the barrier, the outer edge of the road is highlighted and delineated, providing excellent guidance especially during inclement weather conditions.
Low power consumption, minimal light trespass on adjacent properties, and minimal light pollution, especially in non-urban areas, makes this an ideal lighting system for roadways and highways with continuous barriers, construction barriers or rail structures.
The strategy for lighting a viaduct, roadway, or pathway according to the present invention is shown in
The LED luminaire 106 is mounted vertically and is recessed into the barrier 102. The aiming of the luminaire provides light grazing on the barrier surface.
The vertically or near vertically mounted LED luminaire 106 provides uni-directional light along the barrier face. Since the luminaire is integrated into the barrier 102, it does not cause a hazardous projection and does not compromise the crash function of the barrier.
The present roadside lighting system accentuates the roadway shoulder and barrier 102 by providing both beam and field contributions of the photometric distribution. The beam contribution of the LED system highlights obstacles such as the crash barrier 102. The field contribution of the LED system spills light onto the roadway shoulder or other target. Disabled motorists, for example, become more visible to oncoming traffic and very little light will escape (minimize light trespass and pollution) from the roadway structures.
The low energy use and long lamp life of LED systems 106 reduce maintenance and operating costs.
It will be appreciated by one versed in the art that there are many possible variations on these designs, but all are typified by LED lighting systems installed recessed areas of roadside barriers which provide a generally horizontal sheet of light across the barrier. Some known and anticipated variations are described below:
Variations include mounting the LED luminaire in a snow fence, guardrail or other roadside structure, a bollard, a bridge footing, or a tunnel wall. Barriers are made from a variety of geometries. Deployment of the LED lighting system is compatible with most conceivable barrier geometries.
The LED luminaries can be connected to electrical power supplies or operated from a portable power supply such as generator, fuel cell, or battery storage. In addition, alternative renewable supply such as photovoltaic assemblies can also be used as the power source.
| Number | Date | Country | |
|---|---|---|---|
| 60592656 | Jul 2004 | US |
