Technical Approaches to Developing Policy: Use of the FHWA Traffic Noise Model to Identify Noise Screening Parameters

Several state department of transportation policies implementing the Federal Highway Administration noise regulation (23 CFR 772) include noise screening provisions that identify project parameters that allow for application of a screening procedure as an exception to the requirement to perform a detailed noise analysis using the FHWA TNM 2.5 on all Type I projects as designated by 23 CFR 772. These foundation of these screening procedures fall largely on qualitative approaches to establishing these policy provisions rather than relying on technical approaches to verify the validity of the screening procedure. This analysis uses TNM 2.5 to identify appropriate modeling parameters consistent with the approaches of FHWA technical tools to help guide policy makers to make policy decisions based on objective analysis rather than relying on subjective approaches. We present parameters applicable to noise screening procedures to help identify those projects that need a more detailed analysis and parameters to exempt certain Type I projects.