State Highway 126 Noise Study - Thille Community East and West Ranch - City of Ventura

Rincon Consultants prepared a detailed noise study of existing and future noise levels associated with the Santa Paula Freeway (State Highway 126) on residences of the adjoining Thille Community south of the freeway. The freeway is generally buffered from the adjacent residential land uses by an approximate 40-foot wide linear park that has a variable height and width berm between the walking path and the freeway right-of-way fence.

The purposes of this noise study were to: (1) determine current exterior noise levels at the most affected residences in the two tracts; and (2) estimate the sound level reductions that would result from proposed additions to the existing sound wall/berm in the linear park of West Ranch and the addition of a sound wall on the existing berm in the linear park of East Ranch. Field measurements were conducted for a 24-hour period in the backyard of seven residences and sound level data collected included date, time, duration of measurement (in seconds), Leq, SEL, statistical sound levels (L90, L50, L33 and L10), Lmax, Lmin, and peak (A-weighted). Noise pass-by events exceeding 70 dBA and time history (current sound power level every 10 seconds) were also logged by the sound level meter. Freeway traffic was modeled using the Federal Highway Administration Traffic Noise Model® based on data provided by Caltrans in its 2002 traffic volumes. The analysis included an estimation of the noise impacts created by a freeway-parallel barrier recently constructed on the north side of the freeway, and examination of various wall heights and their corresponding effectiveness.