EVALUATION OF PROPOSED LOW-BEAM HEADLIGHTING PATTERNS

This study evaluated several recent proposals for the low-beam headlighting pattern. The research consisted of (1) documenting the current U.S., European, and Japanese standards, (2) documenting the proposed low-beam patterns, (3) performing a comparative analysis of the proposed beam patterns, (4) developing a set of visual performance functions for low-beam headlamps, (5) defining the representative geometry for the visual performance functions, (6) setting criterion illuminance values for the visual performance functions based on available empirical data, and (7) evaluating the standards and proposals in relation to the criterion values by considering the worst allowed case. The following are the main findings: (1) There is a lack of empirical evidence for evaluating the proposals on certain performance functions, including visual aim, effects of misaim, and homogeneity of the beam. (2) In terms of visibility, none of the proposals (nor existing standards) met our criterion of 33 lux for seeing low-contrast targets on the right side of the road, supporting the notion that we commonly overdrive our low beam headlamps. (3) Because the functional requirements of low beams are multifaceted and complex, it is not surprising that each proposal and standard has its advantages and disadvantages. (4) The relation between seeing illuminance and glare illuminance is likely to capture a substantial part of the functional requirements of low beams. (5) The proposal by Padmos and Alferdinck (explicitly designed to optimize European-type low beam) had the best mean ranking across the individual performance functions. The SAE proposal (based on the current U.S.-type beam, but implicitly designed to bridge the gap between the U.S. and European beams) had the second best mean ranking.

• Corporate Authors:

  University of Michigan Transportation Research Institute

  2901 Baxter Road
  Ann Arbor, MI  United States  48109-2150
• Authors:
  • Sivak, M
  • Helmers, G
  • Owens, D A
  • FLANNAGAN, M
• Publication Date: 1992-6

Language

• English

Media Info

• Features: Figures; References; Tables;
• Pagination: 90 p.

Subject/Index Terms

• TRT Terms: Alternatives analysis; Evaluation; Glare; Headlamps; International; Low beamed headlamps; Luminous intensity; Night; Performance; Proposals; Standards; Visibility
• Uncontrolled Terms: Comparative analysis
• Geographic Terms: Europe; Japan; United States
• Old TRIS Terms: Aim; International standards; Low beamed headlights
• Subject Areas: Highways; Research; Vehicles and Equipment; I91: Vehicle Design and Safety;

Filing Info

• Accession Number: 00626650
• Record Type: Publication
• Source Agency: National Highway Traffic Safety Administration
• Report/Paper Numbers: UMTRI-92-14, HS-041 315
• Files: HSL, TRIS, USDOT
• Created Date: Jan 26 1993 12:00AM