Säker framkomlighet: trafiksäkerhetseffekter på mitträfflade vägar

Arne Carlsson
Urban Björketun

Within the project “Safe accessibility” initiated by the Swedish Transport Administration, development of the use of rumble strips as a measure for improved traffic safety is carried out. Rumble strips are placed in the centre line on roads wider than 7 metres and with a speed limit of 80 km/h or higher. At the request of the Swedish Transport Administration, VTI has completed a study analysing the effect of such rumble strips on the road. The main purpose with central rumble strips is to “wake up” drivers who for some reason unintentionally are starting to pass the middle line. Earlier studies abroad and Swedish in-depth fatal accident studies indicate that this measure would have a positive safety effect, especially on running off the road to the left and head-on accidents. The aim of this report is to study the accident rates on roads which have been equipped with rumble strips in the middle. The most important parameter to study is the rate of fatalities or seriously injured road users (FSI-rate) after the measure (performance of rumble strips) compared to the FSI-rate before the measure. It should also have been desirable to study the course of accidents of the actual accident types. However, it has not yet been possible to perform such studies due to uncertain accuracy in the accident spot determination and description of the accident course. The analysis is based on information about the location of roads with rumble strips from the regional offices of the Swedish Transport Administration and accident data from the data base STRADA in the period 2003–2009. The work is a before/after-study in which accident rate before the milling of rumble strips in the middle of the road is compared with the period after. Some of the roads have been equipped with automatic speed cameras during the project. In the present summary, mainly results from roads which were not equipped with speed cameras are accounted for; 212 objects of the total length of 2,570 km. But 17 of these 212 objects have got a reduction of speed limit in September 2008. Thus there are 195 objects with unchanged speed limit, which consist the main results of the study.



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