In order to obtain information about dirt on road signs and its effect on legibility, three specific problems were investigated: dirt accumulation in real traffic; analysis of dirt on road signs; and the problem of legibility. The measurement of dirt once a week on small road signs mounted at different distances from the road, revealed that under unfavorable conditions reduction of reflected light and of contrast was 75 percent and 95 percent respectively. An analysis of dirt collected from road signs showed that most of the dirt originated from the road surface. Using a proven field method, legibility distances were measured to shoulder mounted road signs in various stages of dirtying. The results for night driving without separate sign illumination demonstrated a marked decrement in legibility, whereas in daylight or with separate illumination, the effects of dirt were very limited.

  • Corporate Authors:

    Uppsala University, Sweden

    Department of Psychology, St Larsgaton 2 S-752 20
    Uppsala,   Sweden 
  • Authors:
    • Rumar, K
    • Ost, A
  • Publication Date: 1974

Media Info

  • Features: Figures; References;
  • Pagination: 14 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00099596
  • Record Type: Publication
  • Report/Paper Numbers: #164
  • Files: TRIS
  • Created Date: Sep 30 1975 12:00AM