The Great Headlight Debate
To require all motorcyclists to display headlights at all times must be a good thing, surely? It is well-known that many motorcycle accidents are caused by car drivers not 'seeing' the rider or his machine. Therefore, if all motorcycles were required to display a headlamp irrespective of weather conditions they could be seen more easily and there would be fewer accidents. Simple common sense, isn't it? If only. The real world is, of course, much more complicated, and our politicians want quick and simple solutions so that they can appear to be seen to be doing something to improve our society.
The 'media' feel the need to encapsulate a story in a headline or a sound bite, in the belief that the public's concentration span diminishes in inverse proportion to the complexity of the topic. 'Speed kills' - is an example. Such over simplification can itself be very misleading if it obscures more complex and relevant causes of a problem. 'Motorcyclists should display headlamps on dipped beam at all times' is another one. Just because a road-user sees a motorcycle headlamp it does not mean that they will correctly estimate its speed of approach. The observer must be able to perceive changes in the size of a distinct outline to form an impression of approach speed.
I believe that the brightness of the headlamp can make such approach-speed estimates more difficult due to the halo-effect of the light obscuring the outline of the rider and machine. If the observer is going to miscalculate the approach speed then I guarantee that they will under-estimate and pull out, rather than delay their manoeuvre.
Over the last few decades, many studies have been conducted around the world into the conspicuity benefits of 'Automatic Headlamps On' (AHO) for motorcyclists. The one common denominator is that the results are inconclusive; namely, a reduction in accidents cannot be guaranteed by applying 'AHO'.
The answer might appear to be the use of daytime running lamps (DRL) instead. This would involve the illumination of one (but preferably two) lights of medium brightness (20 to 30 Watts) so that they are bright enough to draw attention but not too bright as to diffuse the outline of the rider and machine. There is a German car manufacturer experimenting with the fitting of light-emitting diodes on the outer edges of the car's head-on profile to emphasise the vehicle's outline. This appears to be a logical development if you are serious about making vehicles easier to see. Whatever type of daytime lighting you consider, for it to work effectively it must contrast with the background light levels. If DRL were ever to come into effect then perhaps those fitted to motorcycles should be of a yellow hue to prevent them being 'lost' in a sea of white car lights.
I think the Americans were on to something back in the 1970s when the front indicators on motorcycles were hard-wired to be illuminated at all times.
I have been riding all sorts of motorcycles for many years, in all weathers and seasons and I am unconvinced that I am safer with my headlamp permanently on. On regular commuting trips I would often alternate between riding a motorcycle with its headlamp permanently on and another where I could choose when to switch it on. My experience was that car drivers were more likely to pull out into my path when I was riding the former machine. Completely unscientific I know, but such experiences have influenced my thinking on this topic. I believe that a brightly-coloured helmet combined with a jacket with fluorescent sleeves and shoulders is more effective than just a headlight but to keep my options open I replace the standard low-wattage parking lamp in the headlamp shell with a slightly brighter quartz halogen bulb to act as a daytime running light.
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