Traffic noise prediction procedures are used in the design of new highways to determine if noise is limited to specific levels. A previous study evaluated the procedure outlined in NCHRP Report 117 and developed a correction factor which was incorporated into Kentucky's noise prediction procedure. This adjusted NCHRP 117 procedure has been used in Kentucky for the past several years. The Federal Highway Administration has developed a new procedure to predict traffic noise levels. The objective of this study was to evaluate the new prediction procedure, designated as SNAP 1.

Comparisons of measured and predicted noise levels showed that predictions obtained from SNAP 1 yield better results than from the adjusted NCHRP 117 procedure. Therefore, it was recommended that the SNAP 1 prediction procedure be adopted. There is no need for a general correction factor; however, adjustments to specific portions of the procedure may be necessary to optimize the predictions.

Report Date


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No. 565

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Offered for publication by the Transportation Research Board.