Toshi
10 kW
Up to this point I haven't seen a review of the scientific literature regarding the various safety implements that we as riders may choose to use: hi-viz, reflective junk, DRLs whether high- or low-beam, and headlight modulators. Having a bit of spare time I though I'd look through the literature to see if there's data behind the paranoia, and it looks as if there is some evidence indeed.
Torrez LI. MOTORCYCLE CONSPICUITY: THE EFFECTS OF AGE AND VEHICULAR DAYTIME RUNNING LIGHTS. PhD dissertation submitted to the University of Central Florida, 2008. (pdf link, click!) All emphasis in quoted sections below is mine unless explicitly noted. This dissertation, which I just found now thanks to Google Scholar, is a fantastic resource for safety-hounds.
Literature review with regard to daytime use of high-beam headlights, low-beam headlights (DRLs), and headlight modulators:
Literature review with regard to fluoro and hi-viz gear, including reflectivity and the chevron pattern:
Experimental data and conclusions involving age, modulators/no modulators, and motorcycle conspicuity:
My conclusions/long-form Cliffs Notes:
1. There exists much epidemiological evidence that DRLs and daytime high-beam usage reduces accident rates, but this type of study is confounded by selection bias (ie, people who wear hi-viz are safer than those who wear wife beaters).
2. There also exists experimental and basic science evidence that shows that DRLs, high-beam usage, fluoro/hi-viz, and the chevron pattern are detected quicker and more reliably, especially in marginal conditions.
3. Old people have measurably slower reaction times, and this difference is significant enough to make the difference between turning in front of you vs. hitting the brakes. Unfortunately, headlight modulators do not "fix" this problem of old people.
4. Headlight modulators do not show a benefit above DRLs alone in the dissertation above, but in more urban/congested/poor lighting scenarios they might have a benefit.
You can draw your own conclusions from all the above, but I've already drawn mine as illustrated below:
Torrez LI. MOTORCYCLE CONSPICUITY: THE EFFECTS OF AGE AND VEHICULAR DAYTIME RUNNING LIGHTS. PhD dissertation submitted to the University of Central Florida, 2008. (pdf link, click!) All emphasis in quoted sections below is mine unless explicitly noted. This dissertation, which I just found now thanks to Google Scholar, is a fantastic resource for safety-hounds.
Literature review with regard to daytime use of high-beam headlights, low-beam headlights (DRLs), and headlight modulators:
Literature review with regard to fluoro and hi-viz gear, including reflectivity and the chevron pattern:
The colors white, crème, and lime yellow have all been found to be more conspicuous than any other color of vehicle in studies evaluating accident involvement (Allen, 1970; Solomon, 1990). The results from these studies are questionable as there is a high degree of validity as to confounding variables such as individual behavioral characteristics and color selection (do safer drivers choose white cars)
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In the field of emergency vehicle design, it is extremely important in increase conspicuity as much as possible due to the particular types of situations and traffic these vehicles must navigate. In doing so, a large amount of research has been directed toward patterned vehicle applications, mostly overseas (Tijerina, 2003). One such potentially promising pattern is the Chevron pattern, or Harlequin “Battenburg Livery†as it is called in Europe (See Figure 2). This pattern apparently plays off of human perceptual cues by representing similarity to a horizontal barricade or bridge abutment, and consequently increasing conspicuity when applied to emergency vehicles (CVPI, 2004).
Figure 2:
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In a study conducted by (Woltman & Austin, 1973), motorcyclists equipped with fluorescent garments were detected much quicker than those wearing conventional colors under a variety of backgrounds, at a variety of angles. This was especially true under environmental conditions of dust and or dim illumination. As mentioned earlier in regards to vehicular lighting, Olson, Halstead-Nussloch, & Sivak (1981) additionally tested the effectiveness of fluorescent garments on motorcycle detection and found their use to effectively distinguish the motorcyclist from their surroundings via a gap acceptance paradigm. These findings have been supplemented by support from research on pedestrian and bicyclist conspicuity, where virtually every study done has concluded that both fluorescent and retro-reflective garments drastically improve conspicuity (for an exhaustive review see Kwan & Mapstone, 2004).
Experimental data and conclusions involving age, modulators/no modulators, and motorcycle conspicuity:
My conclusions/long-form Cliffs Notes:
1. There exists much epidemiological evidence that DRLs and daytime high-beam usage reduces accident rates, but this type of study is confounded by selection bias (ie, people who wear hi-viz are safer than those who wear wife beaters).
2. There also exists experimental and basic science evidence that shows that DRLs, high-beam usage, fluoro/hi-viz, and the chevron pattern are detected quicker and more reliably, especially in marginal conditions.
3. Old people have measurably slower reaction times, and this difference is significant enough to make the difference between turning in front of you vs. hitting the brakes. Unfortunately, headlight modulators do not "fix" this problem of old people.
4. Headlight modulators do not show a benefit above DRLs alone in the dissertation above, but in more urban/congested/poor lighting scenarios they might have a benefit.
You can draw your own conclusions from all the above, but I've already drawn mine as illustrated below:
I am old...
