Flashing vehicle warning lights have two primary functions. The first is to alert approaching drivers and pedestrians. The second function is to provide information to these motorists on what action to take upon approaching the scene. A large amount of research has been done regarding the science behind warning lights and construction vehicle strobe equipment. This research has shown that the detection of the flashing lights are directly correlated to the intensity of the light. However, also with increased intensity the drivers ability to receive information and act appropriately at a certain level of brightness. What this means is the super high intensity warning lights, although highly visible, can prevent the driver from being able to analyze the safety conditions and act appropriately. This is usually due to the driver being blinded by the lights at night. This can be a very dangerous situation!
Other characteristics of a light, such as the flash rate, on-off cycle, flash pulse shape, and flash duration, also influence our ability to detect warning lights. Regarding strobe lights versus incandescent or rotating warning lights, it appears that the split second flash of a standard strobe light makes it difficult for approaching drivers to estimate distance. Because of this, most strobe lights require multiple units placed close together and flashing in quick succession. Highway maintenance, pavement marking, and construction companies have been using amber warning strobe lights for half a century with great effect and increased safety. Incandescent Warning lights are outdated and much less energy efficient. However, they are not as blinding at night time and allow drivers to analyze the situation much better to avoid hazards. In fact even today in 2020, many government organizations like the Michigan State Police use a single large Incandescent emergency warning light with great effectiveness.
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Surprisingly, in many cases outdated rotating light bars have been proven the most effective in stationary lane closures and roadside hazard situations. That means a 200 dollar used rotating light bar may protect you more than the brand new 3,000 dollar "top of line" LED light bar.
The color of the light also has some effect on its ability to be detected. During the daytime, red lights have been found to be most effective. However, at night time, blue lights are more easily detected and are more likely to be reacted to. Interestingly, amber or yellow lights fall in between these two colors and can be generally effective during daytime or night time conditions regardless of intensity.
In states such as Texas, amber warning lights are allowed to be used in conjunction of with blue lights in order to increase the visibility and respect towards the work zone or incident scene. This is specifically for tow trucks, roadside assistance, and construction vehicles that normally would not be able to use any other warning lights than amber or yellow. The reason that has been given for this surprising allowance is because of the proven effectiveness of blue lights to grab attention and move drivers out of a dangerous lane closure. Law enforcement in Texas has stated that allowing more liberal use of blue emergency lights has caused trouble with enforcing warning light laws in general. However, the added safety has been deemed to be worth the trouble.
Another factor that affects the effectiveness of construction zone warning lights is the number of lights present. Practically, the more the better, but only to a certain extent. One should use reasonable judgment when deciding how many flashing lights are necessary due to the high financial costs. More is not always better and if multiple systems are added, the warning patterns should have different flash rates to provide more