Community Sound Levels: A Comparison of Measured and Estimated Data

Abstract

The Office of Noise Abatement has developed several models of transportation-generated sound levels. These models are useful in studying the magnitude of transportation noise and forecasting the noise reduction of alternative abatement programs. The Community Median Noise Level Model was used to estimate the median sound levels in Medford, Massachusetts. The estimated median sound levels were compared to the measured median sound levels. A total of 18 sets of measured and estimated average median sound levels were obtained, i.e., eight traffic control zones and the total for Medford, for two time periods. The average absolute difference between the measured and estimated average median sound levels was 1.5 dBA. The Community Median Noise Level Model operates on the following parameters: motor vehicle density, mix by type of vehicle, average vehicle speed and shielding due to structures between the noise source and the receiver. Analysis of the Medford data also confirmed the very strong statistical correlation between the median sound level and the decile sound levels. Regression equations were developed and used to generate estimates of the noise pollution level in Medford, Massachusetts.