Road Source Noise Model The dataset contains the noise model results for the Dublin Region showing population exposure to sound from traffic sources. The noise maps show colour coded areas in Dublin based on sound levels in 5 bands. These increment in 5 decibels. The night time band starts at 50 decibels and the 24 hour band starts at 55 decibels. There are two categories of sound sources mapped all roads and major roads (roads with more than 3 million vehicle passages per year). Traffic volumes are averaged to an hourly traffic count over a typical 24 hour day. The supporting dataset Total Traffic Volumes and Road Centrelines for Dublin City is also published on Dublinked. Dublin City Council revised the first set of 2007 road source noise maps to produce the current maps for June 2012. The 2012 Revision of Noise Maps and Action Plans are available to download in kml format at http://www.dublincity.ie/WaterWasteEnvironment/NoiseMapsandActionPlans/Pages/default.aspx