The object was to find the relationship between the reflection properties of the road and the visibility of different parts of the road, and between the reflection properties and visual guidance, in order to ascertain whether the shoulder should be lighter than the carriageway, or vice versa. Visibility and visual guidance were assessed in different conditions by 54 test subjects. The reflection properties had a seasonal variation, with the highest values in the spring and the lowest in the autumn. Visibility of carriageway and shoulder appears to depend mainly on their lightness, while the visibility of edge markings depends mainly on the contrast between these and the carriageway, or the contrast between carriageway and shoulder. The reflection properties of greatest significance for visual guidance are retroreflection of carriageway and difference in retroreflection between carriageway and shoulders. No clear answer was obtained as to whether it should be the carriageway or the shoulder that is lighter, but it appears that increasing the lightness of the carriageway enhances visual guidance more than increasing the lightness of the shoulder or that of the whole road. No consideration was given in the investigation to cost aspects, but these must naturally be taken into account. /TRRL/

  • Corporate Authors:

    Swedish National Road Administration

    Fack S-10220
    Stockholm 12,   Sweden 
  • Publication Date: 1975


  • Swedish

Media Info

  • Features: Figures; Photos; Tables;
  • Pagination: 43 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00139033
  • Record Type: Publication
  • Source Agency: Swedish National Road and Transport Research Institute (VTI)
  • Report/Paper Numbers: TV 125
  • Files: ITRD, TRIS
  • Created Date: Dec 1 1976 12:00AM