Effects of a painted median on lateral position and speed.

This study investigated the effects of a 1 m wide painted median on driver behaviour. To the extent that drivers experience the widening of the median as a narrowing of the available driving space, they are likely to reduce their speed, and thereby increase their safety margins. An additional expected effect of the painted median would be increased separation distance between traffic streams in opposite directions. If such visual measures can be shown to improve safety, they may be a low-cost alternative to a median barrier on narrow roads or roads with a low traffic volume. In this study two types of painted medians are investigated. The first consists of transverse 1 m long lines with 1.5 m distance between them. The second consists of two longitudinal lines 1 m apart, with milled-in rumble strips covering the area between the lines. Speed measurements on one of the sections showed a speed decrease of 2.7 kilometres per hour. Both types of painted medians resulted in increased separation between opposing traffic streams, by about 60 to 75 centimetres, compared to a conventional centreline. (a) For the covering entry of this conference, please see ITRD abstract no. 0612AR242E.