Evaluating Roadside Noise Barriers Using an Annoyance Reduction Criterion

Abstract

The effectiveness of noise barriers is typically assessed as the reduction in A-weighted sound pressure level ( LA). This research indicates that this may not be a valid indicator of the corresponding annoyance reduction. Road traffic noise was recorded behind a noise barrier (barrier sounds) and at a location with no barrier (non-barrier sounds). The barrier sounds, recorded 10–45 m from the road, and non-barrier sounds recorded 50–200 m from the road were of similar LA. Despite this, participants in a listening experiment found the barrier sounds to be more annoying than the non-barrier sounds, an annoyance-difference corresponding to a 3-dB increase in LA. The Loudness level (ISO 532B) and a low-frequency corrected sound pressure level ( LA) were found to be better than LA as indicators of the barrier's annoyance-reduction efficiency.