WSDOT SR-509 General Engineering Services

SR 509 in South King County, is an important North-South corridor used by regional communities and freight traffic. Multiple improvements are planned including construction of four new interchanges along the 3.5 mile extension that will link to I-5.

ENVIRONMENTAL NOISE: For the environmental documents phase, GBG is providing ongoing environmental noise measurement, analysis, and modeling in support of the project. Work includes: monitoring ambient noise influences in the study zone including Sea-Tac airport and Sound Transit Link Light Rail to inform the baseline model; inventory of noise receptors; conducting a feasibility and reasonableness assessment for potential noise barrier locations; and providing a Noise Discipline Report Update in accordance with WSDOT Noise Policy and approved methods documented in the Noise Analysis Approach Memorandum.