Noise, including road noise, is a pervasive form of environmental pollution. There is no better way to reduce road noise than to treat the problem at its source. Asphalt pavement mixes help reduce traffic noise at the point where the wheel meets the road. According to a National Cooperative Highway Research Program (NCHRP) report, quiet asphalt mixes can reduce the need for costly and unsightly sound barriers. Since low frequency noise, which can lead to greater driver fatigue, increases with roughness, smooth asphalt roads benefit not only those who live near a road, but also those who drive across it.
For more information - www.asphaltroads.org/why-asphalt/environment/quiet-pavement/
On-board microphones capture the noise differential as a vehicle transitions from an asphalt rubber surface (ARFC) to a portland cement concrete pavement (PCCP) and then back to smooth and quiet asphalt.