When the hybrid buses were introduced on route 60 in Göteborg, Sweden last summer we bragged about the low noise (3 dB less). The reaction did not wait, after a few days two noise complaints were registered from citizens living close to one of the bus stops. Obviously, we had raised the expectations too much.
A passenger survey showed that 86% of the passengers found the new buses less noisy and the remaining 16% did not notice any difference. A measurement performed at the critical bus stops showed in average even less than the “theoretical” 3 dB from the drive-by measurement.
No doubt, the hybrid buses make a substantial contribution to less noise in the city environment.
European union works hard on decreasing the noise in our cities. An excellent starting point is gathering data and comparing. For anyone interested in statistics I recommend you look into this data base: http://www.eea.europa.eu//themes/noise/dc)
You can also contribute yourself by downloading the NoiseWatch (http://watch.eyeonearth.org/ ) app to your smart phone. Measure inside the bus, tram or train and report it. When you are finished you can review the result at “Eye-on-earth”.
One thing seems clear; actions are needed and increased focus on noise is expected.