Even mild traffic noise has a negative impact on work performance — ScienceDaily

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“What is unique about our study is that we were able to demonstrate a decrease in performance at noise levels as low as 40 dB, which corresponds to the normal noise level in an office environment or a kitchen,” says Leon Müller, a student at PhD in the Division of Applied Acoustics in the Department of Architecture and Civil Engineering.

The background noise consisted of two audio sequences that simulated the passing of trucks at a distance of ten and fifty meters. Both sequences were normalized to the same total interior level of 40 dB.

“The audio sequence simulating the closest passages, where the sound changes significantly as the vehicle passes by, generally disturbed the test subjects the most,” says Müller. “This could be because traffic further away is perceived as more constant drone.”

Housing is being built closer to roads now

The new results emphasize an already problematic situation of negative impact on health and job performance due to traffic noise. In recent years, the distance between roads and newly built houses in Swedish cities has been allowed to shrink, a trend that can also be observed internationally.

Put somewhat simplistically, Swedish regulations for where construction is allowed are based on the average outside noise level over a 24-hour period, which means they don’t take individual passers-by into account. In addition, current regulations do not cover indoor low-frequency noise spikes, which are difficult to avoid and, according to research, more disruptive and therefore more impactful to human health.

In a study modeling low-frequency noise, Jens Forssén, Professor of Applied Acoustics at Chalmers, showed that low-frequency noise is mainly generated by heavy traffic at low speeds and is difficult to isolate even with well-insulated windows and buildings that comply with all building regulations and guidelines for sound insulation.

Reduced vehicle speed can increase indoor noise exposure

“Calculations for different types of façades show that it is difficult to achieve ideal indoor acoustic environments near roads with heavy traffic,” says Forssén. “Reducing speeds is not a solution, as our calculations show that interior noise exposure can even increase at lower speeds.”

In addition, Forssén says that noise and the sound environment is a factor that is often considered too late in the planning process, and that there are advantages that could be achieved if adjustments were made to better utilize the space in terms of noise pollution.

The researchers also agree that the most effective solution would be to avoid urban densification in areas where traffic noise would have too great an impact on health and well-being.