Evaluation of Acoustic Climate Produced by the Installation of Speed Bumps and Rumble Strips in the Urban Fabric.

On the roads of many cities several retarding devices - as speed bumps - are placed to slow vehicles. Furthermore, close to obstacles and crossroads rumble strips are installed to keep the attention of drivers. Speed bumps usually are 5 to 15 cm high and 30 to 300 cm long; the biggest ones are called anti-speed bumps. These so called “raised areas” are made to protect crosswalks from high speed and they are built increasing the traffic floor with connection ramps (with a slope, usually, of 10%). Instead, rumble strips are 0.3 cm high bands of an elastoplastic laminate. Their mutual distance depends on the attention level to activate. To determine the effects on the acoustic climate of the areas where these systems are placed, measurements during the passage of different kind of vehicles (weight and speed) have been made. Transit characteristics over bumps and strips have been identified through analysis of different acoustic descriptors; highlighting differences with those transits at same the speed in other parts of the studied infrastructure where there are no retarding devices. Analysis of main acoustic descriptors (LAE, spectral composition, impulsive events, etc.), allow obtaining interesting consideration on the effects these devices have on the acoustic climate of the studied areas.