Noise Metrics Beyond the 65 DNL/CNEL

Focus Area



Community & Cultural Concerns, Environmental Process







Research Idea Scope

The size of DNL 65 dB noise contours around the nation’s airports has diminished steadily for the past three decades; and now most noise complaints come from persons residing outside DNL 65 contours. Many airports are currently struggling to respond appropriately to noise concerns, particularly those experiencing rapid growth in operations. While some airports have explored the options for reducing the impacts of aviation noise outside DNL 65, most have concentrated efforts within the DNL 65, consistent with FAA guidelines. An on-going ACRP synthesis project will compile the applicable laws and policies, how they are applied regionally, and the state of the practice of noise programs targeted outside DNL 65 at airports.  The Joint Planning and Development Office (JPDO) determined that noise must be aggressively addressed in order to meet the projected capacity requirements of the Next Generation Air Transportation System (NextGen).  While the best practices from the synthesis project will be instructive, further research is needed to identify the most effective methods and metrics to communicate changes in noise exposure that will result from future airport growth and expansion projects.  This research would enable airport planners to more directly and effectively address the public view that any increase in operations is an increase in noise exposure, even when the DNL will remain the same or decrease.  It will identify noise metrics that most effectively address changes in the frequency of operations, define the analysis and documentation necessary to implement those metrics and an optimal means for presentation of results to exposed populations both inside and beyond DNL/CNEL 65 dB contours. 

Suggested By

AV030, Environmental Impacts of Aviation, as specified in the TRB Research Needs Database, 2009.