AN EVALUATION OF RETROREFLECTIVE SIGNING MATERIALS UNDER THE 3-BEAM HEAD-LAMP SYSTEM

The purpose of the study described in this paper is to measure the comparative brightness of contemparary traffic signing materials under both the conventional 2-beam and the proposed 3-beam head- lamp systems. Because most traffic signs are retroreflective, sign brightness is highly dependent on the illuminance supplied by head lamps. A systematic evaluation performed by the authors led to a general understanding of sign luminances for conventional 2-beam performance for Interstate Highway System signs. The design experiment was developed to evaluate the relative change in sign luminance should the 3-beam system be standardized. Photometrically selected 2- and 3-beam head-lamp sets were obtained from 2 lamp manufacturers, installed in standard-size passenger cars, and aligned. Night luminance measurements were made of retroreflective sign materials by using a telephotometer installed at driver eye position. Luminance measurements were taken at 7 distances from the traveled lane on a uniformly graded tangent section of test road. The proposed low beam is not different from the current low beam. The sign luminance under the proposed mid beam is approximately 4 times greater than it is under the low beam. The high beam provides substantially more light, and sign luminance under the proposed high beam is approximately 2 times greater than it is under the current high beam.

Media Info

  • Media Type: Print
  • Features: Figures; References; Tables;
  • Pagination: pp 79-92
  • Monograph Title: Measures of effectiveness, railroad-highway grade crossings and visibility
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00134871
  • Record Type: Publication
  • ISBN: 0309024722
  • Files: TRIS, TRB
  • Created Date: Sep 4 1976 12:00AM