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Volume 461: debated on Monday 18 June 2007

To ask the Secretary of State for Transport if he will provide estimates of the level of noise between junctions five and seven of the M3 motorway in each of the last 20 years for which data are available further to the answer of 27 June 2005, Official Report, column 1261W on the M3. (142773)

Noise data are not available to estimate noise levels between junctions five and seven of the M3 for each of the last 20 years. As explained in the answers of 27 June 2005, assessments of noise severity are made using the “Calculation of Road Traffic Noise” (CRTN model) which use distance from source, exposure, obstacles and traffic levels. Each of these factors varies significantly at any point along the road length. The range would vary between less than 60 dB to more than 72.5 dB at the road surface.

The statement in the answer of 27 June 2005 that the noise level is likely to have increased by around 4.5 dB over the last 20 years was based on the approximate increase in traffic levels over the 20-year period.

To provide retrospective assessments would require assumptions to be made about many of the variable factors which would reduce the accuracy of assessments to an unreliable level.

The Highways Agency has conducted assessments using the CRTN model at specific “noise hotspots” and implementation of a programme of local noise mitigation measures is ongoing.