Abstract Due to the growing population and overly congested roadways, numerous of the roadside construction sites occur at night to reduce the problems of traffic. These sites have continually shown problems caused by their unnatural lighting solutions. The essential problem brought to attention is that of safety, caused by the poor vision, bright lights, shadows, and the glare created by the current lighting types being used.
While looking at these different forms of lighting, one will be able to see and understand which the best permanent solution for roadside construction is. Portable Towers, Balloon Lighting, Headlights, Droplights/Floodlights will all be looked at as possible solutions, as well as the advantages and disadvantages that surround them. The Signal Detection Theory will be used to understand the importance and concern for an effective and safe lighting solution.
It will also be used to understand and analyze the situation in terms of hits, misses, false alarms, and correct rejections. Keywords: Signal Detection Theory, Hit, Miss, False Alarm, Correct Rejection. Daytime lane closures and detours have become a thing of the past due to the constant delays, problems of congestion, high flow of traffic, and high possibilities of accidents. For many years now, State Departments of Transportation as well as the Federal Department of Transportation have scheduled for highway and freeway construction projects at night.
(Huckabee, 2009) The nighttime repair and resurfacing of these roadways has expanded throughout the United States and has caused a problem concerning the safety of these projects, that is without the natural lighting of daylight, are the workers safe and citizens safe with the current lighting solution? (Huckabee, 2009) On many road construction sites that I have personally seen, the primary source of lighting is Portable Light towers. I have also seen combined with these light towers are smaller halogen droplights and stands, lights on the workers hard hats, and spotlights.
In just about every site I have seen the lights tend to be extremely bright, almost blinding, where when I am driving by I can’t even see the cars in front of me, let alone the workers giving instructions. According to the Signal Detection Theory (SDT), in these events, I would be considered a miss. (Foley, 2010) I am driving through and because the lighting is so strong or so poor, I miss the workers instructions and sometimes even the workers themselves.
I also have seen sites where I can see the workers fine but it seems like they cannot see the vehicles approaching, which will also be considered a miss according to the SDT, (Foley, 2010) which can be warning signs for a possible future serious accident and exponential problems. When one cannot see the workers instructions clearly, it is very easy to mistake what they say, thus causing a false alarm. (Foley, 2010) According to the SDT, in this case would be a mistake what you see or hear on the roadside due to the poor lighting conditions (Physical Stimulus) that cause one to perceive something incorrectly.
(Foley, 2010) The problem we are looking at now is the insufficient amount of lighting on roadside construction sites. Most of the time these construction sites have workers working late at night well into the early morning, (Huckabee, 2009) which in this case is an example of top down processing. (Foley, 2010) The physical stimulus, which is the lighting issue, is not sufficient to determine the perception of the light.
The mental factors play an essential role in the perception of the light and in this case it’s the fact that commuters are already at a very tired state of mind and will not be as alert as they are during the day. (Foley, 2010) This combined with the fact that many of these sites are providing insufficient and inconsistent lighting, is simply a recipe for disaster. With the current lighting being used at most of the sites being these large Portable Light towers, one can see that they are extremely ineffective and cause many misses and false alarms.
These towers provide bright light but are aimed directly towards the work area, and create an extremely bright and intense glare that is blinding to motorists and workers alike, depending on the angle one has positioned themselves. (Smith, 2006) One may think that if there is insufficient lighting, then the solution would be to bring more of these light towers and try to strategically place them further away to increase the ability to eliminate shadows and the glare.
(Smith, 2006) But in reality, when one increases the amount of towers and adds their light, the towers amplify the amount of glare and shadows, thus intensifying the issue and intensifying the possibility of hits and misses. (Huckabee, 2009) With these issues taking into account it seems that the common ground and common problem, is the glare created from all of the different types of lights, if one could reduce or eliminate the glare it could make the sites much more safe and operable.
The glare is what makes it difficult for the workers and the motorists to see, this glare also creates dark spots and insufficient lighting areas through shadows. (Smith, 2006) In a partnership and study done by the Illinois Department of Transportation and the University of Illinois, they set out to try to measure and detect this issue and provide a measurement to detect which lighting system would be best for the construction sites. (Huckabee, 2009) The researchers measured the veiling luminance ratio which is the glare from some of the lighting sources on the construction sites.
(Huckabee, 2009) This is the same form of experiment used to test the Signal Detection Theory. (Foley, 2010) The ratio ranges were as follows: ? For extended headlights on a roller: 2. 74 to 3. 55 ?For a portable light tower: 1. 31 to 5. 01 ?For balloon lighting on a paving machine: 0. 02 to 0. 51 (Huckaba, P. 33) Their research showed that the balloon lighting produce exponentially less amounts of glare at their respected construction sites, these numbers equate to a 10 to 15 percent less amount of glare per each light at their locations.
(Huckabee, 2009) According to the SDT, the balloon lighting system will cause for far less misses and false alarms, and increase the amount of hits and correct rejections. With the hits and correct rejections being increased, an individual will be able to see the area, objects, and workers much more clear, while also being able to realize what is not there and be able to have a correct rejection to what is not present.
(Foley, 2010) This research proved that the balloon lighting was far superior to the previous forms of lighting being used at construction sites in the past. (Huckabee, 2009) The style of balloon lighting provides much more visibility with less glare and creation of shadows, as well as providing a larger range of light for workers on the out skirts of where the light was directed, thus illuminating the area and being more safe than the previous portable towers. (Smith, 2006) It attempts to create as close to as natural light, as if it were daylight, as possible.
The balloon lights reflected and shine done from directly above the sites, creating a feeling of natural daylight, thus eliminating the glare and reducing the amount of shadows. With this research and evidence being shown, one must believe that balloon lighting is the preferred method and the most effective to use, as well as being the safest, which is the ultimate goal, to complete the tasks and construction work effectively and in as safe of a manner as possible.
References Huckaba, Dennis A, (2009). Illinois Department of Transportation. Research Pays Off. Safer Nighttime Construction Zones Through Better Lighting. TR News 260 32-34. January-February 2009. Foley, H. J. & Matlin, M. W. (2010). Sensation and Perception, fifth edition. New York, NY. Pearson Learning Solutions. Smith, Bruce W. (2006). Developing a New Temporary Lighting System: From Identification of the Problem to the Design of the Solution. Auburn, Alabama.