The aim of this study has been to compile the regulations and criteria for use and design of warning lines in Norway, Denmark, Sweden and Finland.
Warning lines are used in all of the above-mentioned countries but with different designs regarding colour, width and intermittence. The use of the line is also differing between the countries. Generally, the warning line requests the driver to be careful and it can for example be used as a pre-warning for a succeeding no passing line, or to call for caution when changing lanes.
The main areas of use in the different countries are as follows:
In Norway, the warning line can replace the no passing line, if the road-keeper does not consider that the no passing line should be used. Furthermore, the warning line is used in two-way tunnels, towards roundabouts and intersections, and in front of pedestrian crossings.
In Denmark, the warning line is used on narrow roads when the visibility distance ahead is short, and for guiding the traffic at intersections.
In Sweden, the warning line replaces a no passing line on narrow roads. Furthermore, it is used as a pre-warning of a no passing line on wider two-lane roads.
In Finland, the warning line is used as a pre-warning of a no passing line.
The warning lines are designed with the length relationship 3:1 (line:space) in Norway, Sweden and Finland, whereas it is 2:1 in Denmark. The width can be 0.10 m or 0.15 m in Norway, Denmark and Sweden, and 0.10 m in Finland.
In Denmark and Sweden the warning line is white, in Finland it is yellow, and in Norway it can be either yellow or white, depending on application.