6 Unfortunate Ways Traffic Noise Affects People (Research Findings)

Is one man’s noise another man’s music?

Noise is considered a type of pollution because it is an unwanted stimulus that intrudes into a person’s environment, but it is quite difficult to define in any objective way. Definitions are invariably subjective because noise is a sound that a person does not want to hear (Evans & Stecker, 2004).

Some research suggests that the subjective experience of noise (i.e., annoyance), not the level of noise itself, is the important factor regarding people’s health (Nivision & Endresen, 1993). Much research has examined chronic noise exposure (defined objectively as a critical level of decibel) in relatively large samples.

However, the effects of noise are also influenced by other factors such as personality and meaningfulness of the noise  (Cohen et al., 1986). Babisch and colleagues (2013) emphasize that noise annoyance is largely determined by noise level, so both factors are not independent of one another.

Do we “get used to” noise?

Subjective reports show that people begin to sleep better as they get used to traffic noise, which reflects a so-called habituation process. However, objective polygraphic  examinations of people’s brains do not reveal any changes as people begin to “get used to” noise (Kuroiwa et al., 2002; Xin et al., 2000).

In fact, noise exposure may sometimes lead to increased sensitization to noise (Nivison & Endresen, 1993). It seems that some individuals habituate to noise, while others do not. How people adapt seems to depend on people’s sensitivity or personality (Kawada, 2011).

Predictability and the possibility of controlling unwanted noise has been found to reduce cognitive after-effects of noise exposure (Glass & Singer, 1972). Indeed, stress experiments have demonstrated that control is an important factor in moderating one’s physiological stress reactions (Babisch, 2001).

Noise affects us via two distinct routes

The noise reaction model proposes that noise activates the human organism via a direct and an indirect route. The direct route is determined by the immediate interaction of the acoustic nerve with different structures of the central nervous system, which in turn increases physiological stress.

The indirect route refers to the cognitive perception of noise,  and it is linked to an increase in emotional stress. Both routes activate the autonomic nervous system and the endocrine system, and a long-term overactivation of these  systems may have adverse health effects (Babisch et al., 2013).

Many of us live in noisy environments and seem to do fine, but how does noise exposure in fact affect us physically as well as psychologically. What does research tell us? In this article, I present six unfortunate ways that noise affects us.

6 ways traffic noise affects people

1. Cognitive functioning

Stansfeld and colleagues (2005) examined how aircraft and road traffic noise influenced almost 3,000 children’s cognition and health. The study was cross-national with participants from both the Netherlands, Spain and UK.

The authors found a linear exposure-effect association between chronic exposure to aircraft noise at school (not traffic noise) and impaired reading comprehension and recognition memory in children. Neither aircraft noise nor traffic noise affected sustained attention. In this study, traffic noise did not have a negative impact on children’s cognition. The authors provide a possible explanation:

… sound that shows appreciable variation over time (changing state) impairs cognitive function whereas sound that does not vary (steady state) has little effect. The noise of aircraft flyovers has an unpredictable rise time that might attract attention and distract children from learning tasks. (p. 1948).

One study found that reading scores of children in classrooms near train tracks were lower than scores of children whose classrooms were quieter (Bronzaft & McCarthy, 1975). Another study found that noise affected long-term memory in 9-12 year-old children (Evans et al., 1995).

Yet another study by Tassi and colleagues (2013), involving 20 individuals exposed to daily railway noise and 20 individuals living in quiet environments, found that long-term exposure to railway noise had some unfortunate consequences, reflected by increased reaction times in different cognitive tasks and declines of some parts of the attentional system.

2. Blood pressure

3. The autonomic nervous system

4. Stress

Babisch and colleagues (2001) found increased physiological stress in about 800 women, who were exposed to noise during their sleep. The increased physiological arousal was reflected by increases in catecholamines, specifically noradrenaline. Subjective measures of annoyance or disturbance were positively associated with levels of noradrenaline.

Waye and colleagues (2002) found that workers who were more sensitive to noise showed a higher stress (cortisol) level, and they rated a low-frequency noise as more annoying than workers who were less sensitive to noise.

5. Health

Previous studies on the effect of aircraft noise exposure at children’s schools have reported an association with more hyperactivity symptoms (Haines et al., 2001; Stansfeld et al., 2009; Crombie et al., 2011).

6. Sleep

Proper sleep is fundamental to good physiological and mental helth. According to The World Health Organization, In the European Union, 45% of citizens live in areas where environmental night-time noise levels are considered uncomfortable for sleeping, and approximately 30% of citizens are exposed to night-time noise at levels known to cause sleep disturbance (Graham et al., 2009).

A review by Kawada (2011) emphasizes that noise can cause sleep disturbances. These can be classified into delay of sleep onset, or awakening in the middle of the night, or early morning awakenings. Noise also makes the stages of sleep shallower, reducing the feeling of rejuvenation after sleep. At last, intermittent noise during sleep has more adverse effects than continuous noise (e.g., like aircraft flyovers).