Is this a Surprising Study?

Is this a Surprising Study?

Emergency responders at highway crash scenes sometimes find themselves as victims of secondary crashes while working at the scene of the crash. These secondary crashes often involve serious personal injury or death to the responders. The largest percentage of these incidents involves responders being struck by vehicles traveling through the scene of a traffic crash at night. 

The problem of scene safety for emergency responders has several variables. One of those variables is the choice of the colors for emergency lighting. The current trends within the emergency services call for the maximum use of emergency lighting. These trends create the false belief that emergency responders are protected from the cars traveling through the area of the incident. 

In some cases, the high intensity lights create a temporary condition of blindness that reduces the ability of drivers to maintain control of their vehicles as they approach and proceed through the area of an incident. One possible scenario to consider with respect to the temporary blindness would be when an officer needs to stop traffic from driving through the area of the incident. 

Despite any efforts on the part of the officer to provide the greatest visibility to the drivers moving through the incident zone, such as by wearing retro-reflective clothing, little could be done to compensate for the driver’s poor visibility. Therefore, if the emergency personnel were to step in front of a moving vehicle expecting to be seen and have that vehicle stop per their direction, the possibility of being struck was greatly increased simply because the driver is not able to see them. 

Scene safety may be increased through the study of the color of emergency lighting or the manner in which these lights are used in a stationary setting. The safety of emergency responders could be improved by examining the effect that the color of emergency lighting has on other drivers. 

The problem of scene safety for emergency responders might be best addressed through the use of emergency lighting that can be perceived at the greatest distance while creating the least distraction for those passing through the incident scenes. 

The purpose of this study was to determine the distances that different colors of emergency lighting could be perceived and to evaluate the comments about the visibility of traditional emergency lighting. Specifically, this study addressed the use of white, amber, red and blue emergency lighting. The goal of this project was to determine which of the currently utilized colors was visible at the greatest distance with the least negative influence, thereby warning motorists of the presence of a potential hazard and allowing them to react in a controlled fashion. 

The testing was conducted nightly from 11:00 p.m. to 3:00 a.m. until the sample number of 100 individuals was satisfied. On average, there were approximately 50 vehicles that passed through the rest area during the nights of testing. The sample group consisted of 53 males and 47 females. The ages ranged from 18–68 years of age. The average age of the subjects was 41.71 years of age. The test consisted of each subject viewing a Code 3 MX 7000 roof-mounted lightbar with a monochromatic display. The Code 3 MX 7000 is the most commonly used light bar in service with the Illinois State Police. 
The first color displayed was red, followed by blue, white and amber. Each subject viewed the same intensity of the lights and the same amount of flashes per minute. The subjects were provided with a visual display from the passenger’s seat of the second vehicle. This second vehicle was an Illinois State Police car with a certified speedometer. The stationary display vehicle was positioned two miles away from the start of the viewing area. The Illinois State Police car traveled at a fixed speed of 60 miles per hour. 

Once the Illinois State Police car reached the starting point, the emergency lights on the display vehicle were activated. The subjects were instructed to indicate when they first perceived the emergency lighting. The person who administered the test started a stopwatch upon reaching the starting point and stopped the stopwatch once the subjects indicated that they saw the emergency lighting. The reading on the stopwatch was converted to feet. Additional notes were taken reflecting any comments offered by the subject during the test. These comments or reactions were recorded in an attempt to identify any positive or negative characteristics of each individual color. 

The data analysis consisted of inputting the times and distances into tables for the purpose of comparison. One table represented the results from each of the specific colors as a matter of recorded distances of perception. The second table provided the comments or reactions that were recorded from those test subjects who offered any statements. Any general comments offered during the testing were noted and evaluated. 

The color white was perceived at the greatest distance followed by amber, red and then blue. The color white was seen 916 feet earlier than the amber light, 1359 feet earlier than the red light and 1932 feet sooner than the blue light. There was no variance in the sequence that the colors of the emergency lights were perceived. In each case, white was perceived first followed by amber, red and blue. 

Of the 100 tested subjects, 96 offered comments on at least one color of emergency lighting. The comments about the different colors were broken down into three categories: positive, negative and ambiguous. 

The color with both the most comments, and the most negative comments, was white. The color with the most positive comments was amber. Positive statements on the red and blue colors were equally divided but few in numbers: a half dozen total comments for each compared to over 70 comments each both white and amber. 

The distance tests determined that white was the most visible color. However, and perhaps more importantly, the comments that were offered about the color white indicated that it may not be the best choice for use in an emergency lighting display on a stationary vehicle at night. 

Negative comments primarily characterized the color white as too powerful at close distances and temporarily blinding as they approached the stationary squad car that was displaying the flashing lights. 

This condition was not conducive to creating a safe environment for emergency responders. This study suggested that the use of white light, on average, created an unsafe environment for emergency responders due to the distraction that it created as drivers approached an incident scene. 

In contrast to those comments offered about the color white, 70 test subjects offered comments about the color amber and 67 of them were positive in nature. Therefore, although amber was perceived at a shorter distance than the color white, amber did not negatively impact the viewer’s ability to see or distract them from focusing on what was in front of them. 

The objective data indicated that the color white was perceived at the greatest distance but the subjective data mitigated the desirability of the color white. In order for a motorist to avoid an object he must first perceive it. However, continued visibility as vehicles drive through the incident scene must also be a consideration. Emergency lighting was designed to make the motoring public aware of a potential hazard, not create one. Despite being seen at the greatest distance, the color white should not be utilized on stationary emergency vehicles at incident scenes. 

The color amber was perceived at a slightly shorter distance than the color white, but that difference of distance still allowed plenty of time for the driver to react by slowing, steering or braking. In addition, the color amber did not have the negative characteristics that were identified in the comment’s section of the tables for the color white. 

Additional research should be performed to determine the effects of inclement weather and the impact of daylight on the tested colors of emergency lighting. 

The lightbar used in the test, the Code 3 MX 7000, was equipped with rotating red, white and blue lights, flashing red and blue lights, and an amber arrow stick. With respect to this available combination of emergency lighting, the emergency responders who have taken a position at an incident scene should extinguish the rotating or flashing white lights and utilize the amber arrow stick. No additional equipment would need to be purchased for those vehicles equipped with these or similar lightbars. 

The recommendation for those vehicles without a light-bar would hold that the officer should utilize whatever emergency lighting he has while en route to the incident scene. However, once he has reached the scene the officer should activate the flashing amber lights and extinguish all flashing or rotating white emergency lighting. 
The use of the amber arrow stick will provide a color that is easily perceived and will provide direction to the drivers of those vehicles approaching from the rear of the emergency vehicle. The emergency vehicles will still be visible, as amber lighting has been proven to be more visible than red or blue, but the lighting will not compromise their safety or the safety of the other emergency responders at the scene of an incident. 

This recommendation may seem radical in light of current practices that often call for the use of the greatest amount of emergency lights as possible. The belief that emergency lighting provides a safety barrier is false. Emergency vehicles should not be utilized as traffic control devices: that is what cones, flares and signs provide. Emergency vehicles provide transportation for emergency responders and a platform for emergency lighting. 

Emergency lighting provides a message to the motoring public. The message should not be confusing; it should be clear and simple. The message should convey that emergency responders are ahead, trying to provide assistance to someone who needs help. Emergency personnel can send that clear and simple message by utilizing the most effective and least distracting display of emergency lighting and by applying concepts found in the area of traffic incident management. 
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