Noise indicators of road and rail traffic noise based on subjective perception, psychological and physiological parameters

The direct effects of sound energy on human hearing are well established and accepted, but previous research about the effects of noise exposure on medical parameters has been carried out mainly under laboratory conditions with established sound indicators like Lden or Lnight – using the A-weighting. The relation between psychoacoustic indicators and objective health parameters is less well investigated, also in soundscape studies.
The two main objectives of the project “INTRANOISE” were to study the effect of road and rail traffic sound on human sleep patterns and explore the relationship between the subjective perception of 100 test persons and objectively measured psychoacoustic and physiological parameters. The crucial point was that all measurements were done in the free field during real-life situations, thus avoiding unrepresentative laboratory test arrangements. A standardized method for objective acoustic measurements in residential environments of test persons was developed based on experiences of the involved researchers. The total quantity and quality of a test person’s acoustic exposure is assessed by a time-synchronized comparison between the results of a traffic-noise-annoyance-questionnaire and psychoacoustic parameters.
Different applications of international noise indicators based on the obtained data were additionally analyzed and results will be shown and discussed. Results indicate that outdoor traffic noise is a significant factor for indoor subjective noise ratings of people and they are able to clearly distinguish between different noise sources. Indoor noise is the dominant factor for physiological reactions during sleep, leading to observable cardiovascular reactions.