Q&A with Nils Haferkemper, DUT Darmstadt
DVN: I was very surprised by your experiments which show almost no influence of switching low beam. How do explain we are using these features on motorcycles for so many years?
I do not know the historical background, because it is just accessible in detail from protocols, but my opinion is that in the end it was a simple solution and it is pretty comprehensible that switching on the low beam during daytime was assumed to increase conspicuity. From the literature I was not able to find any field test leading to this consequence.
DVN: How do you explain the great different on visibility distance between low beam and LED DRLs? Is it because the shape, the illuminance on the eye, the colour of the light or is there any other reason?
The major advantage to low beam is the extremely high luminance of the DRLs.
This is what mainly contributes to the observed effects. Of course the colour is new to most road users, but the German federal highway research institute (BASt) found out in a static experiment that there is no significant effect of colour in conspicuity. Also from the physiological side this can be neglected. It is not sure which influence the shape has because that was not a point of research for us, but it would be interesting to have a study about that!
DVN: Don’t you think there would be a big confusion between motorcycles and cars if they are equipped with the same lights?