This presentation reports about the findings from an extensive research on the evaluation of characteristics of acoustical signals in the surrounding of typical urban traffic situations. The research also determines the most important attributes to ensure their safe detectability of acoustic signal to be produced by AVAS.

The main conclusions drawn from the research are as follows:
  • Individual one-third-octave bands (low or high frequencies) being prominent ensure the detection of vehicles from ambient conditions.
  • Relatively few signal elements are used to detect the sound of internal combustion engine vehicles.
  • Low-frequency engine orders play an important role on the detection.
  • Essential parameters:
    – Tonality
    – Time variance (e.g. Modulation, impulsiveness etc.)
    – Spectrum outside of the ambient.