4: Adverse Effects of Traffic Noise

Adverse effects of traffic noise occur in different degrees in a substantial part of the world population, especially in areas with a dense population and dense transportation networks. As a consequence, traffic noise is a global issue. This chapter reviews and systematizes the research on adverse effects of traffic noise in residential areas. Four routes are distinguished through which noise exerts its primary influence: sound masking (communication disturbance), attention (concentration disturbance), arousal (sleep disturbance), and affective/emotional responses (fear/anger). Results presented can be used to design the best practical ways of reducing noise-induced effects through the reduction of noise exposure.

Traffic noise causes adverse effects and it is widespread and increasing. Lambert and Vallet (1994) estimated that in the European Union (EU) during daytime approximately 77 million people (i.e., 22% of the total population in 1994) were exposed to transportation noise levels exceeding 65 dB – a level which many countries consider to be unacceptable. Almost 170 million Europeans (49%) lived in, what the authors call, grey zones, that is, zones that do not ensure acoustic comfort to residents. Depending on the country, road traffic noise annoyed between 20% and 25% of the population. Even though the uncertainty in these estimates is very large, there is no doubt about the high prevalence of noise annoyance in the EU. A survey (Al-harthy and Tamura, 1999) in Muscat City, Oman, illustrates that noise and noise annoyance are not confined to the industrialized societies, but grow very fast in cities in the developing countries. The length of the paved roads in Muscat City increased from not more than 50 km in 1975 to 156 km in the old city and 1213 km in the entire city in 1995. This explains the finding that in 1995 (lack of) “quietness” caused the highest dissatisfaction in a sample of 452 inhabitants. It was higher than the dissatisfaction with the 12 other aspects of the surrounding that were rated, such as “public facilities” and “safety”. The above figures illustrate that traffic noise is widespread in the industrialized countries, as well as in urban areas in the developing countries. The growing transportation network with increasing traffic intensities is an important driving force of the increase in the worldwide noise exposure.