NCHRP Project 25-45
In 2013, I&R began research on heavy truck noise sources for the National Cooperative Highway Research Program. I&R's goal was to determine the height distributions and spectral content for heavy trucks, building from earlier research sponsored by Caltrans and the National Coorperative Highway Research Program (NCHRP). Utilizing acoustic beamforming technology, I&R was able to create acoustically visual source maps to indicate predominant noise sources.
During the research, four sites in Northern California were visited along with sixteen additional sites in North Carolina. These sites had an array of different pavement types and speed limits. In total, the noise source regions for 1289 heavy trucks were mapped from vehicle traffic on public highways.