This analysis is not routinely undertaken. High conspicuity retro-reflective tape, when used, is applied to the rear and sides of heavy vehicles and trailers to improve conspicuity, particularly in the hours of darkness and in poor visibility conditions such as heavy rain. The tape is likely to have most effect, therefore, on side or rear impact accidents occurring in those conditions.
In 2005 (the latest year for which figures are available) in Great Britain there were seven fatal and 25 serious accidents involving HGVs of 7.5 tonnes or over, hit in the rear or side, in rainy daylight conditions, and 40 fatal and 138 serious in fine or rainy conditions during the hours of darkness. Using the estimates of effectiveness set out in the Loughborough University report on retro-reflective tape, such tape might have helped to avoid 10 fatal and 36 serious HGV accidents in 2005. However, the report also pointed out that its findings are subject to very considerable uncertainty. For example, results were based on research comparing vehicles having no conspicuity markings at all with vehicles fitted with retro-reflective tape. In this country HGVs are already equipped with side marker lamps, side retro-reflectors and retro-reflective rear marker plates. Therefore the effect of the tape might not be as great here as in some other countries.