Lighted Crosswalk Systems
The federally designated In-Roadway Warning Light (IRWL) system, which is called the Smart Crosswalk™, is a lighted crosswalk system. With this system, a strong street crossing safety measure is established. The lighted crosswalk ensures pedestrian safety with embedded in-pavement signal lights and dependable yellow flashing warning signs. The Smart Crosswalk™ is proven to significantly lower the chances of pedestrian crossing accidents.
A number of in-pavement signal lights are placed across a roadway in front of the crosswalk lines. The lights are activated before entering the crosswalk by the pedestrian. Once activated, the roadway flashing signal lights are focused towards approaching drivers warning that the crosswalk zone is occupied.
Manual on Uniform Traffic Control Devices (MUTCD)
Beginning in 1994 numerous stringent third party studies and testing procedures using LightGuard System Inc.® technology successfully culminated in the acceptance of IRWL enhanced crosswalk lighting system into the Federal Highway Administration MUTCD. The Millennium 2000 edition incorporated IRWL enhanced crosswalk systems into Section 4L, and they have been adopted as a standard across the United States.
The Smart Crosswalk System™
The LightGuard IRWL enhanced crosswalk system operates on low voltage Direct Current (DC) power. The IRWL system can use either solar power or locally available Alternating Current (AC) power which is converted to 12v DC. Inside each embedded in-pavement signal light module there are 16 high-output LED lamps. The IRWL are positioned so that they are slightly above road grade assuring they will always be visible even with significant debris accumulation.
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.
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.