The Gold Standard
The LightGuard Systems®, Inc. In-Roadway Warning Light (IRWL) product is the “Gold Standard” for all in-pavement crosswalk systems. LightGuard Systems® originated lighted crosswalk systems, which we call The Smart Crosswalk™, as an effective traffic calming system for pedestrian crossings.
The Smart Crosswalk™ is the system that was the evaluated for inclusion of IRWL Systems as a standard into the Federal Highway Administration Manual on Uniform Traffic Control Devices (MUTCD), Section 4N. We were involved in the drafting of regulatory language developed for the MUTCD standard for IRWL enhanced crosswalk systems.
—The original IRWL crosswalk system ... More
Early in the development of the signal head module, glass lenses were tested but were quickly abandoned because they were too brittle. Today we have a patented clear acrylic “Dove Prism”™ lens sealed into the signal head.
This solid one piece design seals the prism lens and prevents external water intrusion and moisture buildup. The patented clear acrylic dove prism is not subject to UV degradation, an industry wide problem noted in the past.
The prism directs the beam of light so that it is oriented toward the motorist and is visible at both long and short range. The in-pavement LED signal lights are directed towards the approaching motorist, away and outward from the crosswalk. All the light beams placed across the road will merge at the eye level of the approaching motorist in what is termed the “Zone of Convergence™”.
This zone is determined by the posted speed limit and is located approximately 200 to 400 feet in advance of the crosswalk. For details see: Zone of Convergence and Speed Table Chart
The light beams will enter through the human eye flashing at the Enlighten1™ flash rate/pattern that was developed in cooperation with the University of California, Berkeley Vision Detection Laboratory. Our enhanced flash rate is preferred because the light will travel to a primitive part of the brain that notices motion and movement designed to capture the driver’s attention. This flashing rate/pattern is proven by studies to enhance IRWL system signaling capability.
The signal light modules are directed towards approaching motorist and are visible to the motorist but not the pedestrian. The design intent of the Smart Crosswalk™ system is to remove a “false sense of security” on the part of the pedestrian when crossing.
The ability to view the crosswalk signal lights by the motorist and not the pedestrian was originally mandated by the California Traffic Controls Devices Committee (CTCDC). Through an 8-year process of “Authorization to Experiment” by the Federal Highway Administration and though stringent evaluation, the Smart Crosswalk™ uni-directional lighting system design was developed specifically to provide the best IRWL enhanced crosswalk safety for the pedestrian.
Most IRWL systems are retrofitted to existing crosswalks.The first step is the layout pattern in determining the placement of each IRWL module by lane and crosswalk locations. (See Visual Installation Guidelines)
Once the layout is determined the next step is to saw cut for the IRWL system wiring. The saw cut is generally no wider than .5 inch wide and no greater than 2 inches deep. Either conduit or direct burial wire can be utilized. Once the saw cut has been completed, the locations for the base plates are identified and the depression holes are bored into the road surface. (For complete in-depth instructions please see the LightGuard Installation Manual.)
The standard 10 inch diameter x 1.5 inch deep base plate is made of a ultra-high strength composite material. It is designed to be permanently embedded into the roadway. This allows for any in-roadway warning light fixture that becomes damaged or inoperable to be repaired with an easy to install replacement.
For “snow country” use, we offer a snowplow blade resistant steel base plate (“Product – Snow Plow Blade Resistant Base Plate”). The case hardened steel base plate has wing tips on either side of the signal module and a center nose bridge. When a snow plow blade strikes the base plate, the blade is lifted up and over the top of the signal head module. The steel base plate is 14 inches in diameter and is no more than 1.5″ deep.
Benefits of a “One Time” saw cut… One Word … Reliability!
We recommend the reliability of hard wired vs. wireless systems. Wireless equipment systems over time have proven to result in operational performance issues, malfunction, increased maintenance, and unusually high replacement costs. We have also noted that this type of system has numerous hidden issues as well, such as overcast, fog, cloudy periods, or just plain shade from trees or nearby buildings. We believe “One saw cut, is worth a thousand batteries”…!
The following are layout diagrams for typical mid-block crosswalks at both 2 and 4 lane crossings:
Two Lane IRWL Systems Layout Diagrams:
Four Lane IRWL Systems Layout Diagrams:
—Self Clearing Base Plate ... More
There is a slight elevation of the IRWL module above the road grade. This feature is intended to prevent the signal light from being blocked by debris, this is a critical design aspect. Our LightStar™ IRWL significantly reduces the potential for liability due to blocked light to the motorist when critically needed. This visibility factor should be a decidedly important design consideration when specifying IRWL enhanced crosswalk systems for any type of application.
Our IRWL signal modules are designed with a self clearing feature called “Debris Free™” built into the base plate. These are fluted channels located across the face of the base plate. This design compresses air from vehicle tires to “jet out” the accumulated rubble through the fluted air channels in the base plate face.
The photo on the upper right shows our IRWL still visible with some accumulated debris (struck less often when located on center line). The photo on the lower right shows a signal module where this self clearing feature has kept the LED light clear of accumulated road trash.
The selection of power source, either A/C or solar, can be dependent on the distance from the IRWL system site to the power source. Should costs related to bringing a standard power supply to the Power Control Unit (PCU) location be excessive, the solar option can be utilized. Be aware, however, that in locations where solar systems are subjected to shaded conditions a decrease in solar charge to the batteries will occur.
LightGuard staff will be glad to assist you in assuring proper system operation and recharge for your location with the use of our LGS – SolarCalculatorTool™. Contact us for assistance.
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