LDEN 2017 Contours

To view noise maps for an average 24 hour period from all road traffic sources in ‘Google Earth’, click on the link below and download the associated ‘zip’ file. The unzipped sound contours can then be opened in Google Earth. (You need to have access to Google Earth on your computer in order to open these files.)

24 Hour Noise Maps for All Road Sources

The sound contours displayed in this file are the Lden (accumulated sound levels for the day, evening and night-time periods). The Lden value is comprised of the average of the calculated sound values for the day period (7am-7pm), the evening period (7pm-11pm) plus 5 decibels and the night period (11pm to 7am) plus 10 decibels.

Sound levels that are below those that are required to be reported to the European Commission are represented by the absence of colour; there are no Lden contours representing values below 55dB(A).

The Noise Action Plan does not provide any values for desirable/undesirable exposure values for Lden. However values for a standalone day-time period are provided: greater than 70 decibels is undesirable and less than 55 decibels is desirable.

The sound contours are not based on measurements but rather on computer modelling as required by EC Directive 2002/49/EC relating to the assessment and management of environmental noise. See here for more detail. In summary this directive requires member states to determine:

• (a) exposure to environmental noise (by means of noise mapping which uses methods of assessment common to the member states),
• (b) ensuring that information on environmental noise and its effects are made available to the public and
• (c) adoption of action plans.