When the Lights Go Out: An Infrequent but Lethal Road Danger
Barry Beith / Human Factors / Transportation
According to an article in the May 17, 2010 News & Observer, a young man died on the road between Pinehurst and Sanford near the intersection of US 1 and NC 42. The report indicated that he hit a car head-on in the northbound lane of US 1. The car he hit had no lights on according to witnesses. One witness said the car was stopped. The driver of the dark vehicle was also killed. The young man hit it at speed head-on, suggesting that the “dark” vehicle was heading the wrong way or somehow got turned around in the northbound lanes. The police told his father that “they doubted that he ever saw it.” What a waste. High school aged, football star, coming home from seeing his girlfriend at her home in Pinehurst. Gone in the blink of an eye.
Gone in the blink of an eye that could not see the danger ahead in the road. Even something as large as an automobile. Even though his car lights were working fine. While this blog opens with a tragic story, its point focuses squarely on issues of visibility, conspicuity, and night vision. When our highway speeds outrun our headlights, our vision at night fails to protect us. When an object is dark, our closing rates can preclude our ability to see, think, and react. The end result is often fatal.
3M Corporation in the 1970s developed a product line referred to as “retroreflective” material. It was a fabric coated in a liquid which contained thousands of small hemispheric shaped “half” beads which possessed a mirrored concave interior. When struck by a light source, the hemispheric mirrored shape concentrates the light and actually reflects a more concentrated light back toward the source. As a result even poorly lit objects could be seen from much larger distances and the conspicuity of these objects is enhanced many fold. Conspicuity is different from visibility in the sense that an object can be made more conspicuous relative to other objects in the visual field. In other words, within the field of visibility, some objects become more conspicuous than others, thereby drawing our attention to them and increasing our awareness of them. All objects are visible, but some standout more. The beauty of this technology is that it exists in varying forms such as fabric and paint. It is cheap, time-tested, and true. More importantly, it is passive, requiring no energy source, no switch, no effort or workload.
Now to the point, we have all seen this technology on bicycles and baby carriages. We have seen it a thousand times on jogging clothes including jackets, shirts, and shoes. We have used it on highway signs, motorcycles, helmets, and even on the rear of truck trailers. Research demonstrated years ago that when retroreflective tape was used around the border on the rear of a truck trailer, following drivers could better judge their closing rate and adjust their speed or lane changes accordingly and more safely. I know something about this because in the 70s, I did research on coal mining that used different patterns of retroreflective fabric on miners’ suits to improve their conspicuity to equipment operators and each other in the mines. Today mining safety inspectors as well as other miners continue to use such materials on their coats and helmets.
Another positive aspect of the material is that it is cheap relatively speaking to other options for improving safety. How you might ask does this relate to the tragedy with which I opened this blog? How, in all these years, in a danger filled activity such as driving at night, have we decided that cars should have only “active” lighting systems? Why do car manufacturers not employ “passive” materials known to increase conspicuity and, as a result, safety in night driving situations. Here we have a technology that has been around for 40 years that improves visibility and conspicuity, increases attention grabbing characteristics of objects, makes drivers more alert to dangers, increases the distance at which drivers can effectively function at night. Something that has been in use for many years in highway related designs and yet, is not employed as a part of the required safety system in the design of automobiles.
Like the high mounted center tail brake light which immediately reduced rear collisions in traffic, such a simple and elegant human factored answer to the problem could easily be realized. Imagine that the young man had been able to see the car beyond his headlights, it glowed and attracted his attention, he slowed immediately, if for no other reason than curiosity, and he realized early enough that it was something in the wrong place at the wrong time, at all costs to be avoided.
Had automobile designers, manufacturers, and regulators employed such a low-cost, simple improvement as requiring the implementation of retroreflective paint on the automobile, perhaps one young man driving from Pinehurst to Sanford on a dark night in North Carolina would be still be alive.
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Louise Hewitt
I think this is awesome. Why don’t we do this?
I can see that initially, getting used to an unexpected reflection will take adjustment. But that is no case against it.
Legislators. Take note.
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