Noise Round 4 Road Agglomeration (Lnight)

This is a polygon dataset of the strategic noise mapping of agglomeration roads for Round 4 (2022), representing the situation during 2021, in the form of noise contours for the Lnight period for Cork, Dublin and Limerick noise agglomerations.
The dB value represents the annual average Lnight indicator value in decibels over the night time.
The strategic noise mapping of agglomeration roads includes all roads within the three noise agglomeraiton areas.
The values are calculated at a height of 4.0m above local terrain, not measured, and should be treated with caution when looking at specific locations.
The strategic noise mapping of agglomeration roads was undertaken by Noise Consultants Limited inside the three noise agglomerations, under contract to the agglomeration local authorities, with support from Transport Infrastructure Ireland (TII).
The outputs of the Round 4 noise mapping exercise were generated using a new common noise assessment method for Europe (CNOSSOS-EU), as set out in the revised Annex II of Directive 2002/49/EC, and they are not directly comparable to any strategic noise maps previously generated under Rounds 1 to 3, as these revised methods calculate noise emissions, propagation and residential population exposure differently from the methods used in previous rounds.
The noise maps are the product of assimilating a collection of digital datasets, and over the last 15 years there have been ongoing significant improvements to the quality of the digital datasets describing the natural and built environment in Ireland, therefore the Round 4 strategic noise mapping includes changes to the model input datasets being used, compared to previous rounds, particularly related to the road network modelled, the terrain model, building heights, traffic flows and ground cover.
The strategic noise maps should not be relied upon in the context of planning applications for noise sensitive developments in the vicinity of the mapped sources.

本数据集为第四轮（2022年）城市集聚区域道路战略噪声地图的多边形数据集，代表2021年的噪声状况，以科克（Cork）、都柏林（Dublin）及利默里克（Limerick）三个噪声集聚区域的夜间时段（Lnight）噪声等值线形式呈现。
本数据集中的分贝（dB）数值，代表夜间时段的年度平均夜间等效声级（Lnight）指标值。
本次城市集聚区域道路战略噪声地图覆盖上述三个噪声集聚区域内的全部道路。
本数据集的数值为基于当地地形上方4.0米高度的计算结果，而非实测值，在针对具体点位进行研判时需谨慎对待。
本次城市集聚区域道路战略噪声地图项目由噪声咨询有限公司（Noise Consultants Limited）承接，服务于上述三个噪声集聚区域的地方政府，并获得了爱尔兰交通基础设施局（Transport Infrastructure Ireland, TII）的支持。
第四轮噪声评估项目的成果采用欧盟修订后的《2002/49/EC指令》附件二中规定的欧洲通用噪声评估方法（CNOSSOS-EU）生成，该成果无法与第一至三轮项目生成的战略噪声地图直接对比——因本次修订后的方法在噪声排放、传播及居住人口暴露量的计算逻辑上，与此前各轮使用的方法存在差异。
本噪声地图是整合多类数字数据集的成果。过去15年间，爱尔兰用于描述自然与建成环境的数字数据集质量得到了持续且显著的提升，因此与此前各轮项目相比，第四轮战略噪声地图所使用的模型输入数据集已进行了调整，尤其在建模道路网络、地形模型、建筑高度、车流量及地表覆盖等方面均有优化。
对于映射声源周边的噪声敏感开发项目的规划申请，不得直接依赖本战略噪声地图的结果。