Acoustic measurements on Rennes Métropole

This data layer makes it possible to consult the results of acoustic measurements related to noise emissions from transport infrastructure traffic (road and rail) on Rennes Métropole. These measurements were carried out in accordance with standard NF S 31-085 on the characterisation and measurement of road traffic noise and standard NF S 31-010 on the characterisation and measurement of environmental noise. These data come from the results of studies commissioned by the Energy and Ecological Transition Service of Rennes Métropole or brought to its attention. Acoustic levels at a "t" moment are also inseparable from noise sources. This is why traffic counts carried out simultaneously, over representative periods (excluding school holidays and public holidays, weekends), which are likely to vary, should be included. The various acoustic indicators relating to this data expressed in dB(A*) are as follows: \- LAeq (equivalent continuous level, which corresponds to the average sound level over a given period. This is the best-known energy indicator, as it is used in French legislation (Order of 5 May 1995 NOR: ENVP9540148A); \- Lden (Level day enening night), which is an overall harmonised indicator at European level calculated on the basis of equivalent levels over the three 24-hour periods: day, evening and night, to which additional corrective terms are applied, taking into account an increased sensitivity criterion for the evening and night periods; \- Ln (Level night) which is the European index for night noise (22h-06h). The Lden and Ln indices are used for drawing up strategic noise maps (Order of 4 April 2006 NOR: DEVP0650177A). *dB(A): unit of measurement used for environmental noise measurements incorporating a weighting that reflects the sensitivity of the human ear, which naturally attenuates certain frequencies for the same sound energy. The limit values for noise contributions in dB(A) on the facades of buildings are as follows: LAeq day (6h-22h): 70 (road/LGV) | 73 (conventional railway) LAeq night (22.00-6.00): 65 (road/LGV) | 68 (conventional railway) Lden: 68 (road/LGV) | 73 (conventional railway) Lnight: 62 (road/LGV) | 65 (conventional railway)