PROBLEMS OF ACTIVE PROTECTION AGAINST ROAD NOISE

In densely populated countries a reduction in the noise level near roads of between 15 to 20 db(a) by the increase of distances from roads and by the erection of noise screens can be achieved only with difficulty. In the case of acoustic screens undesirable side effects (impairment of safety, the landscape, open spaces, lack of ventilation, etc) must be considered. Placing the road in a tunnel gives a high degree of noise reduction, but one must examine whether the high expenditure of energy for the lighting and ventilation of road tunnels and the high costs can be borne in the long run. Attempts should therefore be made to reduce as far as is practicable the noise emission from the traffic. Possibilities in this regard are discussed. /TRRL/