The report is an attempt to describe the effects on accidents of compulsory use of running lights - low beam or special lamps - during daylight in Sweden. The study is carried out on traffic accidents with personal injury in Sweden. The before and after periods are two years before and two years after the operative day of the law, October 1st 1977. The use of running lights in the before-Period was roughly speaking 50% and in the after-period over 95%. The basic assumption is that the use of running lights in daylight influences multiple accidents in daylight and only those. The method used is to study the relation of daylight to darkness numbers of multiple accidents. The corresponding relation for single vehicle accidents is taken as control. Multiple accidents during daylight are estimated to decrease by 11% or 900 accidents per year from before to after. This change is not significant on the 5 "1 level. A subdivision into accident types, where the first three groups are accidents between motor vehicles, gives the following results 10 % reduction for accidents where the vehicles have opposing directions 9% reduction for accidents where the vehicles have crossing directions 2 % reduction for coincident directional accidents 21 % reduction for accidents between motor vehicles and cycles or mopeds 17 % reduction for accidents between motor vehicles and pedestrians The greatest reductions are found for accidents between motor vehicles and unprotected road use.re. Alternative methods for the latter accident types, without use of single accidents distribution on daylight and darkness as control, gives a 5 to 13% reduction for cycle and moped accidents and l to 5 % reduction for pedestrian accidents. These effects are not significant on the 5% level. The estimated total effect depends on how accident data are subdivided and what method is used for accidents with unprotected road users. The estimates vary from 6 to 13% reduction - from the before-period to the after period - of multiple accidents during daylight or 450 to 1100 less police reported accidents with personal injury per year. The estimated effects are not significant on a 5% level. A subdivision according to weather gives no obvious dependence. This might be a result from the fact that in the before-period, the use of running lights was highest when the external light was poorest i.e. when the effect of running lights was expected to be highest. (Author/publisher)
Abstract