The purpose of the study was to examine the effectiveness of audible warning devices (AWD's) on emergency vehicles in terms of aural detectability. Community noise intrusion and opportunities for AWD optimization were also investigated. Measurements were made of sirens, automobile insertion loss, and human detection performance in real-life and simulated situations. Warning effectiveness distances were calculated for three representative situations: (1) Rural environment with vehicle windows closed and radio on; (2) urban environment with vehicle windows open and radio off; and (3) suburban environment with vehicle windows open and radio off. It was concluded that reliance on present audible warning devices to warn drivers in traffic is not justified. To be loud enough to warn in all ordinary circumstances, the sound level of audible warning devices would have to be increased greatly -- producing intolerable community noise. Present audible warning devices can be improved; more uniform horizontal forward radiation and higher frequency sounds would increase detectability. The analysis procedure can provide the basis for an objective measure of audible warning device performance.

  • Supplemental Notes:
    • Prepared by Bolt, Beranek and Newman, Inc., Cambridge, Mass.
  • Corporate Authors:

    Society of Automotive Engineers (SAE)

    400 Commonwealth Drive
    Warrendale, PA  United States  15096

    Bolt, Beranek and Newman, Incorporated

    50 Moulton Street
    Cambridge, MA  United States  02138

    Transportation Systems Center

    55 Broadway, Kendall Square
    Cambridge, MA  United States  02142
  • Authors:
    • Potter, R C
    • FIDELL, S A
    • Myles, M M
    • Keast, D N
  • Publication Date: 1977-8

Media Info

  • Pagination: 150 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00169215
  • Record Type: Publication
  • Source Agency: National Technical Information Service
  • Report/Paper Numbers: DOT-TSC-OST-77-38 Final Rpt., HS-021 948
  • Contract Numbers: DOT-TSC-868
  • Files: NTIS, TRIS
  • Created Date: Jan 30 1989 12:00AM