Residents’ Perceptions and Attitudes Toward to Line of Sight Wall and Conventional Concrete Noise Wall for Traffic Noise Abatement

Traffic noise abatement is one of the Indiana Department of Transportation (INDOT) strategic commitments to environmental mitigation and our neighborhoods. However, the INDOT Traffic Noise Policy applies solely to Type I projects and the constructed cost of conventional noise walls is approximately $2 million per linear mile currently. In many areas, the cost-effectiveness criteria established in the INDOT traffic noise policy are exceeded with the result that the areas are not eligible for federal-aid funding for noise abatement. Consequently, the residents in these areas are dissatisfied that no noise reduction measures are provided to them. To address the above issues, one alternative option was adoption of an optional line of sight (LOS) wall policy. While the LOS wall does not fit into the current noise wall policy and could not use federal funds for construction, it may achieve a 5 dBA noise level reduction and provide a measure to improve customer satisfaction at a less expensive cost than conventional noise walls. A study was performed to evaluate the total performance of the selected LOS walls. The two main tasks included evaluation of the field acoustic performance of the selected LOS walls and identification of the residents’ satisfaction with the selected LOS walls. This paper reports the analysis procedures, first-hand data and main findings from the second task. Pre- and post-installation community surveys were conducted to identify the residents’ attitudes toward both conventional noise walls and LOS walls, their perceptions of the costs and effectiveness of the conventional noise walls and the LOS walls, and third party funding for LOS walls. In the authors’ opinion, such information will be useful to state DOTs not only to upgrade their traffic noise policy and enhance LOS wall design, but also to improve customer services.