RELATIVE VISIBILITY OF INCREASED LEGEND SIZE VS. BRIGHTER MATERIALS FOR TRAFFIC SIGNS. FINAL REPORT

Static and dynamic legibility studies were conducted to investigate the effects of level of reflectivity, letter series, stroke width, letter spacing, font, letter height, and driver age. The dynamic study also considered the effect of sign size and retroreflectivity on the level of conspicuity. As expected, driver age had the largest effect on both legibility and conspicuity. In fact, the daytime legibility for older drivers is almost as poor as night legibility. Level of retroreflectivity, letter series, and letter height all had a significant effect on legibility. Increases in letter height resulted in proportionate increases in legibility up to about 600 ft (183 m). In most cases, stroke width, letter spacing, and font were not significant; however, with fully retroreflective signs, a narrow stroke width significantly increased the legibility of high-contrast signs. Using spacing narrower than the standard spacing did significantly reduce legibility. With regard to conspicuity, 36-in. (0.91-m) signs with type I sheeting were found to have detection distances equivalent to 24-in. (0.61-m) signs with type VII sheeting. Black-on-white signs were found to have much shorter detection distances than black-on-orange or white-on-green signs. Cost comparisons (excluding life-cycle costs) using the data available suggested that larger signs with type I sheeting were less expensive than smaller signs with type VII material which provided similar performance. The effects of other materials with brightness between type I and type VII were not of significant magnitude to provide reliable cost evaluations.

• Record URL:
  https://rosap.ntl.bts.gov/view/dot/74763
• Corporate Authors:

  Last Resource, Incorporated

  309 Armagast Road
  Bellefonte, PA  United States  16823

  Federal Highway Administration

  Turner-Fairbank Highway Research Center, 6300 Georgetown Pike
  McLean, VA  United States  22101
• Authors:
  • Mace, D J
  • Garvey, P M
  • Heckard, R F
• Publication Date: 1994-12

Language

• English

Media Info

• Features: Figures; References; Tables;
• Pagination: 49 p.

Subject/Index Terms

• TRT Terms: Age; Alternatives analysis; Brightness; Color; Costs; Days; Drivers; Legibility; Lettering; Night; Reflectivity; Retroreflectivity; Sheathing; Signs; Size; Traffic signs; Visibility
• Uncontrolled Terms: Driver age
• Old TRIS Terms: Letter height; Letter spacing; Sign colors; Stroke width
• Subject Areas: Finance; Geotechnology; Highways; Materials; Operations and Traffic Management; Safety and Human Factors; I35: Miscellaneous Materials; I73: Traffic Control;

Filing Info

• Accession Number: 00675283
• Record Type: Publication
• Report/Paper Numbers: FHWA-RD-94-035, Rept No. 94-01, 3A2a 1272
• Contract Numbers: DTFH61-90-C-00015
• Files: NTL, TRIS, USDOT
• Created Date: Mar 15 1996 12:00AM