Road traffic noise impact assessment based on the difference between existing and future traffic noise levels

New York City has established standards for impact assessment based on the difference in traffic noise levels between the existing and future conditions. This difference is directly related to the logarithmic ratio of passenger car equivalents under the two conditions. The FHWA Traffic Noise Model 2.0 predicts noise levels from data based on the number of vehicles classified by category, average vehicle speed, and the distance to receptor. The model results can be used to determine the change in noise level between the existing and future conditions. Both approaches give essentially the same result. In heavily populated urban centers like New York City, where the measured baseline existing noise is not only from road traffic but also from many other noise sources such as air-conditioning units, people noise, construction activities, etc., a new approach is needed to determine the change between the existing and future noise levels. This approach utilizes data obtained from field noise measurements which are conducted with and without trucks. This realistic procedure can be used to determine the number of new heavy trucks that could be introduced into the existing traffic stream without exceeding impact thresholds set by the New York City Noise Regulations.