Motor vehicle conspicuity: an assessment of the contribution of retro reflective and fluorescent materials.

Accident data suggests that the conspicuity of large vehicles, and the perception of closing speed to them, are contributory factors in accident causation. Ergonomic principles indicate that improved luminance and colour contrast, as well as outlining the vehicle form, are likely to increase conspicuity. A review of previous research, current on-the-road practices and the materials available shows that retro-reflective and fluorescent materials can be applied to vehicles to increase their night-time and daytime conspicuity. If applied in outline form, such materials may also assist in judgements of separation distance. Experimental work confirmed the benefits of retro-reflective and fluorescent materials, particularly if applied in outline form. The ECE104 marking formats performed at least as well as, and frequently better than, the current ECE70 markings in terms of conspicuity. The markings assisted in the detection of a pedestrian located beside the vehicle and visual discomfort, caused by the luminance of the materials, was minimal. The introduction of the ECE104 marking formats was therefore recommended. Public opinion indicated that the colour red was recognised with 99% accuracy and was strongly associated with signifying the rear of a vehicle. It would therefore be beneficial to use red markings to the rear of vehicles but only if the following recommendations are met: they must be employed as full or partial contours, applied in conjunction with the ECE70 markings and be located no closer than 200mm to the vehicle’s brake lights. It is also recommended that combined fluorescent-retro-reflective materials should be permitted under ECE104, subject to their meeting the colorimetric requirements, since they are likely to be of benefit to daytime conspicuity and some night-time aspects, whilst imposing no severe disbenefits