This is a polygon dataset of the strategic noise mapping of roads, which were identified as those roads exceeding the flow threshold of 3 million passages per year, in the form of noise contours for the Lnight (night) period for Dublin and Cork agglomerations and the major roads outside of the agglomerations. The dB value represents the average decibel value during the Lnight time. Any direct comparison of the Round 3 versus Round 2 results should be carefully considered, as changes to the model input datasets used between these rounds may be significant. This may especially apply to the terrain model used, while there may be improved building height data, & improved traffic flow data with fewer assumed flows. There may also be some revisions to the actual road network modelled in Round 3. The noise maps are the product of assimilating a collection of digital datasets, and over the last 10 years there has been significant improvements to the quality of the digital datasets describing the natural and built environment in Ireland. This has led to the strategic noise models giving much more reliable noise results with much less tendency to over predict the impact. UPDATE (February 2019): The Regional roads in 26 Local Authorities (LAs) outside of Dublin, and Cork have now been amended by Transport Infrastructure Ireland (TII). The original road maps had included some significant stretches of roads (~20%) that were below the 3 million vehicles movements/annum reporting threshold. These road sections have now been removed and revised Regional road maps have been released by TII. This TII review process has resulted in an update of the National road map that is reported to the EEA. The EPA has also updated our website to reflect these changes, and we will also look to provide relevant links to the Final LA Noise Action Plans (when completed): http://www.epa.ie/monitoringassessment/noisemapping/