DRIVER PERCEPTION OF JUST NOTICEABLE DIFFERENCES OF AUTOMOTIVE SIGNAL LAMP INTENSITIES. FINAL REPORT

The National Highway Traffic Safety Administration (NHTSA) often receives petitions for determination of inconsequential non-compliance from manufacturers regarding vehicle lamp intensities which fall just outside the performance limits as specified in Federal Motor Vehicle Safety Standard (FMVSS) 108. They assert that most drivers could not notice the difference, and thus the non-compliance is inconsequential. Typically, a non-compliance regarding intensity has been deemed inconsequential to safety when the performance has been less than 25% above or below the boundary limit. This study empirically evaluated the just-noticeable difference (JND) of several signal lamp types under typical ambient illumination and viewing distance conditions to provide an objective basis for assessing waiver requests. The procedure involved a paired comparison of standard light sources filtered to simulate color and intensity differences. Based on the findings, a difference of up to 25% from FMVSS 108 intensity requirements appears to be a reasonable criterion for use in decisions regarding the inconsequentiality of non-compliant signal lamps.

• Corporate Authors:

  Comsis Corporation

  8737 Colesville Road
  Silver Spring, MD  United States  20910

  National Highway Traffic Safety Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • Huey, R
  • Dekker, D
  • Lyons, R
• Publication Date: 1994-9

Language

• English

Media Info

• Features: Appendices; Figures; References; Tables;
• Pagination: 41 p.

Subject/Index Terms

• TRT Terms: Automobiles; Compliance; Luminous intensity; Signal lights
• Identifier Terms: Federal Motor Vehicle Safety Standards
• Subject Areas: Highways; Vehicles and Equipment; I91: Vehicle Design and Safety;

Filing Info

• Accession Number: 00677675
• Record Type: Publication
• Source Agency: National Highway Traffic Safety Administration
• Report/Paper Numbers: HS-808 209
• Contract Numbers: DTNH22-92-D-07002
• Files: HSL, TRIS, USDOT
• Created Date: May 16 1995 12:00AM