A noise analysis is required when the Washington County Transportation System Plan (TSP) has been updated to reflect a higher classification or additional travel lanes on a road section than were in the TSP at the time of the adjacent development.
In general, the County's will install noise walls if the following criteria is met:
At least a five decibel noise reduction to housing units adjacent to the construction
At least a five decibel noise reduction to housing units adjacent to the noise wall
Meet a cost-benefit criteria per housing unit
Noise walls are typically not warranted if:
Frequent openings, such as driveways, sidewalks and fire accesses
Non-residential buildings, such as businesses, schools and cemeteries