Continuous or broken edge line on roads? A study shows that the type of edge line did not have an influence on travel speed, neither in daylight nor at night. The aim of the study was to investigate whether travel speed on two lane roads is influenced by the type of edge line. Two types of edge lines were assessed in the study: broken line, which is the standard line type on Swedish two lane roads, and continuous line. Another aim was to investigate whether there is a difference in durability for the two line types. The study was carried out on a 4 km long segment of the two lane road riksväg 55 between Malmköping and Strängnäs, during a time period of three years. In the second and in the third year, the function of the edge lines was measured, in terms of retroreflection and luminance coefficient. The results showed that the type of edge line did not have an influence on travel speed, but the preview time was significantly higher for the continuous than for the broken edge line. No difference in durability between the two line types could be observed during the two years the study was carried out. From a traffic safety and comfort perspective, the results point toward the use of continuous edge lines on two lane roads, at least on hilly and curving roads. However, it is still uncertain which of the two lines has the lowest life cycle costs. (Author/publisher)
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