President George Bush Turnpike Eastern Extension Pilot Noise Analysis

Project Description

Paul Carpenter Associates, Inc. (PCA) was retained by the North Texas Tollway Authority (NTTA) to review compliance of the Eastern Extension of the President George Bush Turnpike from State Highway 78 to Interstate Highway 30 Re-evaluation of the Final Environmental Impact Statement and Section 4(f) Evaluation, June 2008, with the governing federal highway traffic noise regulation and Texas Department of Transportation traffic noise policy. As a result of traffic noise complaints, PCA was also requested to design additional noise mitigation measures for four residential communities within Section 31 of the President George Bush Turnpike Eastern Extension (PGBT-EE) in Rowlett, Texas for review by the NTTA board.

PCA performed peak hour noise measurements along the northbound and southbound PGBT-EE in a total of twelve locations in order to validate a project-specific TNM2.5 model developed from PGBT-EE design plans, as-built cross-sections and grading plans and locations of existing noise walls, retaining walls and privacy walls. In addition, traffic data collection and vehicle classification counts were performed. Once the TNM2.5 model was validated, PCA evaluated three noise wall mitigation design options. Since the mitigation designs did not require federal review or approval, PCA established a project-specific mitigation design goal to achieve at least an 8 to 10 dBA noise level reduction at as many noise-sensitive receivers as possible. PCA also performed parallel noise wall investigations, utilizing the TNM2.5 Parallel Wall Subprogram, to determine the effects of multiple reflections and the need for absorptive noise walls and/or treatments applied to existing retaining walls, concrete rails and Frontage Road noise wall surfaces. PCA worked closely with NTTA engineers to identify engineering constraints that would affect the overall design and placement of noise walls as well as to develop comprehensive average noise wall costs (material and construction estimates) for each mitigation option.

A final report was prepared, which documented PCA's analysis methodology, mitigation design options and associated costs. PCA presented findings to the NTTA and representatives of the four homeowners' associations.