40 – Why an acoustic barrier?

Protect residents from noise from the highway and trains

There is strong evidence that the use of well-designed barriers is effective in locally reducing transport noise between 7 and 12 dBA for highways, and up to 15 dBA for trains.

A noise difference is noticeable from 3 dBA. So these barriers will have an impact on the quality of life of citizens.

There are several ways to protect local residents from highway noise. You can either move the receiver away from the noise source, or isolate the receiver from the source. Since you can’t move the houses nor the highway, the main and most effective solution is building acoustic barriers. It is also the most subsidized technique by governments. Several scientific studies converge on this subject.

In Quebec, the Ministère des Transports (MTQ) has published a guide “Fighting road traffic noise“.

The National Institute of Public Health of Quebec (INSPQ) has studied several solutions and issued several scientific opinions on this issue.

Avis Scientifique sur une politique de lutte au bruit environnemental – INSPQ (2015)

Their recommendations include both effective control measures on the source (muffler, engine brakes, tires, speed reduction etc.), as well as measures to control the propagation of noise. In this last category, the INSPQ indicates:

“An expert report concludes that there is strong evidence that the use of well-designed screens is effective as a method of locally reducing transport noise because, on the basis of a before and after efficiency measure , they reduce noise between 5 and 12 dBA. » P.72

“Installing 3 to 4 meter high acoustic screens can reduce railway noise by up to 15 dBA. » P.234
INSPQ
Listen to the difference : with and without noise barrier

The INSPQ also produced the following graph which assesses the effectiveness of noise mitigation measures. We can see that acoustic barriers are among the most effective measures.

Meilleures_pratiques_amenagement_effets_bruit_environnemental INSPQ (2018)

In this publication, the INSPQ illustrates, among other things, the fact that a difference in noise is perceptible from 3 dBA. Therefore, installing an acoustic barrier will have a flagrant effect for residents on their quality of life.