HMMH conducted a detailed noise barrier design study in close coordination with design engineers Fay, Spofford & Thorndike, Inc. (FST).
HMMH used the latest version of the FHWA's Traffic Noise Model (TNM Version 2.5) to conduct the noise modeling, compute noise levels and noise barrier performance throughout the study area, and to develop appropriate height, length and location for the noise barrier. The modeling accounted for the variability in the local terrain, especially adjacent to the interstate. The model also included the noise shielding effects of the rows of homes and buildings, to predict more accurately the sound levels at receivers behind these building rows.
A model validation effort compared the measured sound levels to the sound levels predicted by the traffic noise model using the traffic counted simultaneously. The recommended noise barrier is 2535 feet in length with height ranging from 8 to 25 ft above the ground. In addition to providing substantial noise reduction to 58 residences impacted by traffic noise, the barrier benefits 42 more dwellings less seriously affected by noise.
HMMH presented the results of the study to members of the public, local officials and representatives of the local press during two separate public meetings.