The Environmental Planning Division has developed the Day/Night Noise Level Calculator, an electronic assessment tool that calculates the Day/Night Noise Level (DNL) from roadway and railway traffic. This is a web-based application of the existing Noise Assessment Guidelines (NAG). Derivations of the basic noise equation from the noise regulation, 24 CFR Part 51 Subpart B, were applied to a new application of the NAG.
Noise from aircraft and loud impulse sounds are addressed through this tool as well. Aircraft noise data, available from the neighboring airports, may be input for inclusion in the total site exposure. Loud impulse sounds are similarly accommodated once their presence has been confirmed.
Site Acceptability Standards:
Additional guidance on how to calculate the DNL for a proposed HUD-assisted project is available in the Department's guidebook The Noise Guidebook and the regulation 24 CFR Part 51 Subpart B, Noise Abatement and Control.
After using the DNL Calculator following the directions in the User's Guide, users are encouraged to provide feedback on how the calculator may be improved.
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