Type B Strategic Noise Map (Noise Affected Areas). Prefectural Order No 71-2018-07-13-005 of 13 July 2018.

The European Directive 2002/49/EC on the assessment and management of environmental noise aims at a harmonised assessment of exposure to noise in the Member States. It defines them as representations of data describing a noise situation according to a noise indicator, indicating exceedances of limit values, the number of persons exposed. Noise maps are not prescriptive. These are information documents that are not legally enforceable. As graphic elements, however, they can supplement a Local Planning Plan (LDP). As part of an Urban Travel Plan (UDP), maps can be used to establish baselines and target areas where better traffic management is needed. To quantify the level of noise emitted by an infrastructure over an average day, two indices are used, the Lden index and the Ln index, recommended for all modes of transport at European level: Lden: representative indicator of the average level over all 24 hours of the day, LN: representative indicator of the average sound level for the period 22h-6h. Noise levels are assessed using digital models (computer software) incorporating the main parameters that influence noise and its propagation (traffic data, field topology, meteorological data, etc.). The noise maps thus produced are then cross-checked with the demographic data of the areas concerned in order to make an estimate of the population exposed to noise pollution. The noise level shown on the noise maps is derived from a calculation method which gives approximate values and often higher than reality (maximists) in a noise area considered critical. An in situ noise control can determine precisely the noise to which a construction and its occupants may be exposed. The map of the sectors affected by noise (type B map) represents the sectors affected by noise in the prefectural sound classification orders adopted pursuant to the Ministerial Order of 30 May 1996 and based on a forecasting trend in traffic.《欧盟2002/49/EC号环境噪声评估与管理指令》（European Directive 2002/49/EC）旨在统一欧盟成员国的噪声暴露评估工作。该指令将噪声地图定义为依据噪声指标描述噪声状况、标明噪声超标情况及受噪声暴露人数的数据可视化成果。噪声地图不具备强制约束力。此类文件仅为参考资料，不具有法律强制执行力，但作为可视化图形载体，可作为地方规划方案（Local Planning Plan, LDP）的补充内容。在城市交通规划（Urban Travel Plan, UDP）中，噪声地图可用于确立评估基准与需优化交通管理的重点区域。为量化某一基础设施在单日平均时段内的噪声排放水平，欧盟层面针对所有交通方式推荐使用两类指标：Lden指数与Ln指数：Lden指数：代表单日24小时的平均噪声水平；Ln指数：代表22时至次日6时时段的平均噪声水平。噪声水平评估采用整合了影响噪声及其传播核心参数的数字模型（计算机软件），相关参数包括交通数据、场地地形、气象数据等。据此生成的噪声地图随后会与受影响区域的人口统计数据进行交叉核验，以估算遭受噪声污染的人口规模。噪声地图上标注的噪声水平源自特定计算方法，该方法得出的数值为近似值，在被认定为关键的噪声敏感区域中，结果往往高于实际噪声水平（即高估场景）。现场噪声检测可精准测定建筑及其居住者可能暴露的噪声环境参数。噪声影响区域地图（B类地图）展示了依据1996年5月30日部长令制定、基于交通预测趋势的省级噪声分类指令中划定的噪声影响范围。