Traffic noise predictions are normally conducted in accordance with the Department of Transport CRTN method. This method takes into account the speed and flow of the traffic, the road gradient, HGV content, source and reception point heights, perpendicular distances to noise source line etc, plus any barrier attenuation or ground absorption effects on route.
The Department of Transport’s Calculation of Railway Noise report provides a method of predicting railway noise levels based on a knowledge of train types, train speed, numbers of locomotives and carriages, state of track and ballast, intervening ground cover, site layout etc. It is primarily intended for the assessment of sound insulation requirements for new railways, but can also provide guidance in land use planning near existing railways.
PPG24 assessments or their recent ProPG equivalents (either by measurement or prediction) combined with BS 4142 assessments (where necessary) can be carried out and followed up with general design recommendations for window glazing selection, fence/wall attenuation solutions and room ventilation requirements, etc.
By way of example during 2003 the company assisted Mouchel Consulting Group and Transport for London on the A406 London North Circular Road Improvement Scheme by means of base line noise surveys, traffic noise predictions in accordance with DMRB procedures, including identification of noise sensitive properties and the classification of noise nuisance areas. Other examples include large housing developments incorporating new road inputs and increased traffic movements.