Report numberRA-2007-116
TitleTest setting with additional road markings on 70 km/u roads
SubtitleEffect on speed
AuthorsAn Dreesen
Stijn Daniels
Published byPolicy Research Centre for Traffic Safety 2002-2006
Number of pages68
Document languageDutch
Partner(s)Universiteit Hasselt
Work packageOther: Infrastructure and space

On several through roads in Flanders, the normal speed limit of 90 km/h is often lowered to 70 km/h outside built-up areas, 50 km/h inside built-up areas, and 30 km/h in school zones. Even though the system is legally consistent, for the road user it’s not always easy to know what the current speed limit is. Using additional road markings as indication of the actual speed limit could be a cheap and fast way to remind road users of the speed limit.


In this report describes the research on the effect of additional road markings on speed. Two types of additional road markings have been studied to see if compliance to the speed limit was better after installing them.


One type of road markings consists of adding a new broken line along the existing edge line in both directions. Another type that was examined is adding a number ‘7’ along the edge line, again in two directions. Both types were added on 2 locations on through roads with a speed limit of 70 km/h. An information board was added to indicate the meaning of the markings to the road users.


The method used to define the effect is a before- and after study, with correction for the general trend by using measured speed of a comparison group of locations, one for each test location. Due to the nature of speed data, limited analysis was possible.


Analysis of the speed data on all test locations revealed that adding both types of markings and the according information board, resulted in an increase in V50 on these locations.


Adding the broken line without the information board, and adding the information board on the location with the ‘7’-marking also increased the V50 on these locations.


Due to the nature of the speed data, it could not be examined if the variance in speed changed because of the extra markings.


The theory of planned behaviour gives some insight in the defining factors for a change in speed, but the reason for the increase of speed can not be determined.


Even though this test situation is different from implementing this measure on a bigger scale in Flanders, implementation without further investigation is not recommended.

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The Policy Research Centre for Traffic Safety carries out policy relevant scientific research under the authority of the Flemish Government. The Centre is the result of a

cooperation between Hasselt University, KU Leuven and VITO, the Flemish Institute for Technological Research.


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