- Author
- Howett, G. L. | Kelly, K. L. | Pierce, E. T.
- Title
- Emergency Vehicle Warning Lights: State of the Art. Final Report.
- Coporate
- National Bureau of Standards, Washington, DC
- Sponsor
- Law Enforcement Assistance Admin., Washington, DC
- Report
- NBS SP 480-16, September 1978,
- Distribution
- Available from National Technical Information Service
- Keywords
- warning systems; luminaires; motor vehicles; regulations; visual perception; luminous efficacy; color; luminous intensity; flash lamps; reviews; phase; motion; signal lights; transportation lighting
- Identifiers
- emergency vehicles; state of the art
- Abstract
- Information is presented concerning all aspects of emergency-vehicle warning lights (EVWLs). A survey of the present situation includes: the non-uniformity of state EVWL laws; the factors entering into the choice of an EVWL configuration; a list and photographs of a variety of EVWL types; and a list of EVWL manufacturers and distributors. Background material relating to the perception of EVWL signals includes: an analysis of general warning-signal perception; a description of the visual stimulus pattern confronting a driver being approached by an emergency vehicle from various directions; and a summary of the characteristics of peripheral vision (including luminous efficiency, color perception and discrimination, and flicker and movement perception). Perceptual factors affecting the conspicuity of EVWL signals are discussed, including: effective intensity; flash rate; on-off ratio; pulse shape and flash duration; spatial sweep of beam; color; number and spatial pattern of lights; cross-sectional area; motion; temporal phase relations; and the role of the background. Physical measurements on EVWL units are described, including: angular intensity distribution and beamspread; flash rate; pulse shape and flash duration; effective intensity; color; and variables in rotating devices. A glossary, extensive enough to be helpful in reading the technical literature, is included.