The nationwide Travel Management Planning process provides an unprecedented opportunity to plan for and manage the soundscapes of U.S. National Forests. Since the first Executive Order governing motorized recreation, issued by the Nixon administration in 1972, federal agencies have been required to consider noise propagation when analyzing the potential impacts of motor vehicle activity on public lands. The Travel Management Rule, published by the Forest Service in 2005, also requires that decisions to designate roads, trails, and other areas for motorized use take engine noise into account. However, accurate and affordable methods for modeling potential noise impacts are critical gaps in the information needed to complete this process. The goal of our project was to identify the best methods for forecasting potential noise propagation from off-road vehicle activity in forested or other natural ecosystems. In this document, we describe the different factors that affect environmental noise propagation, discuss our review of existing spatial models and software packages, and explain how to install and use the new tool that we developed: SPreAD-GIS. Although we developed this tool for use in the Forest Service Travel Management Planning process, we hope it will be useful for a wide range of transportation and recreation planning and research applications.  

https://aeinews.org/aeiarchive/docs/TWS_SPreAD_usersguide.pdf