The performance of modern retroreflective material in the road traffic environment I: visual acquisition and sign legibility

The use of retroreflective sheeting has been primarily driven by the photometric performance of the sheeting with little regard to assessing the effectiveness of various sheeting types in meeting drivers' signing needs under different road traffic scenarios. The advent of microprismatic sheeting allows for much greater freedom in the design of the photometric performance of the sheeting. The questions of where and whether to use microprismatic sheeting has generated increased confusion in the State Road Authorities and Local Governments and has become a major issue within Standards setting bodies. The objective of this paper is to provide some guidance as to the performance of signs made from the different types of sheeting and how each should best be used to benefit the driver. Two partial models of visual acquisition of sign information are proposed that are relevant to the retroreflective performance of traffic signs. They are a visual scanning-type model and a visual conspicuity-type model. The major consequence of the two models for retroreflective sheeting is that they operate over different distance ranges. A model of the sign luminance as a function of distance from the sign is proposed based on a review of previous legibility studies. The model suggests two criteria, one for an adequate sign luminance that will meet driver requirements for most situations and one for optimal sign luminance that will cater for high luminance complex surrounds, older drivers and sign conspicuity.


  • English

Media Info

  • Pagination: 19p
  • Monograph Title: Transportation Research Board 83rd Annual Meeting compendium of papers CD-ROM, January 11-15, 2004, Washington, DC

Subject/Index Terms

Filing Info

  • Accession Number: 01390549
  • Record Type: Publication
  • Source Agency: ARRB
  • Files: TRIS, TRB, ATRI
  • Created Date: Aug 23 2012 4:55AM