Projects

Holmes Road Traffic Noise

Holmes Road Traffic Noise

tdot highway traffic noise modeling

The Holmes Road from Riverdale Road to Hacks Cross Road, Shelby County widening project is a Type I project in accordance with the Federal Highway Administration (FHWA) noise regulation, Procedures for Abatement of Highway Traffic and Construction Noise, 23 CFR 772. The proposed Holmes Road design will be for a 2-mile section of four-lane highway (two lanes each direction, with turn lanes at intersections), potentially impacting several hundred existing private residences.  The project required a noise study to identify noise impacts and to evaluate noise abatement for those impacts.  The noise study was conducted in accordance with the Tennessee Department of Transportation’s Policy on Highway Traffic Noise Abatement (TDOT’s noise policy) and Section 5.3.4 (Noise) and the Tennessee Environmental Procedures Manual.

The project’s Computer Aided Design (CAD) files were used to create project files that were imported into FHWA’s approved modeling program, TNM 2.5, for conversion to the applicable TNM model types.  Topographic data provided in the original design files was limited, with supplemental elevation data obtained from extracted Google Earth meta-data gathered by converting the CAD drawings to Google Earth .kml files.  Each residence in the area of potential effect was drawn in as a separate barrier structure, utilizing existing data and Google Earth imagery.  Residences were too sporadically placed and with varying orientations to use the “building rows” concept of TNM.  Design year 2040 traffic projections provided by the traffic engineer and TDOT were used for the noise analysis.  Directional traffic was modeled with 50% of the total count per direction per lane. 

The study determined that the project will create traffic noise impacts.  A total of six properties were predicted to be impacted.  The impacted land uses include five Category B residences and one Category C trail within a residential neighborhood.

Noise abatement was evaluated to mitigate the predicted noise impacts in accordance with TDOT’s noise policy.  Two of the impacted residences have direct driveway access to Holmes Road and noise abatement (via barriers) are not feasible for these properties.  The three other residences are isolated impacts, and noise abatement is not reasonable for these properties.  Similarly, the trail impact was evaluated and found to be equivalent to one residential impact; therefore, noise abatement is not reasonable for this property.  Based on noise abatement for all predicted noise impacts being either not feasible or not reasonable, noise abatement was not proposed for this project.