A coarse inventory conducted by the Raad voor Transportveiligheid (RvTV) has shown that trucks backing into an driveway in the rural area are relatively often involved in collisions. During this manoeuvre the trailer is on the roadside of oncoming traffic. These collisions seem to suggest that the trailer is noticed to late despite side marker lamps that are mandatory since 1995. TNO Human Factors has conducted a study in commission of the RvTV after the visibility of side marker lamps and other possibilities to improve conspicuity of trailers. The study consisted of two parts. Firstly, sight distances were calculated for a side marker lamp, and secondly a literature survey was conducted to the collisions in question, the effect of side marker lamps and the possibilities to enhance the conspicuity of the trailer. The calculations showed that under good viewing conditions the side marker lamps can be seen from a large distance. However, environmental dirt, the visual angle of the lamps and scattered light of the headlights can reduce the sight distance (both the influence of environmental dirt and scattered light of the headlights were not taken into account). No research on the presented problem was found. Other research did show that side marker lamps increase the conspicuity of trailers. To further improve the conspicuity of trailers (retro)reflective materials have been used. Research indicated that applying (retro)reflective materials to the rear end and sides reduced the number of collisions with trailers. The calculations showed that the side marker lamps ought to be clearly visible from a large distance. However, not all aspects that influence the sight distance could be taken into account. It is recommended to organise a field test to conduct measurements so that the calculations can be extended. In this way the other aspects that influence the sight distance can be taken into account. (Author/publisher)
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