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Ramboll - Stoneridge Mall Residential Project 158850326.2 6/11 Confidential Figure 1. Outdoor Activity Areas Highlighted in Red. The Ldn at the two outdoor courtyards and two rooftop decks were predicted using CadnaA, an environmental noise modeling program that conforms to ISO 9613 and ISO 17534. The calculation method used was based on the FHWA’s Traffic Noise Model (TNM) version 2.5. The sound sources in the model included local roadways (e.g., Stoneridge Road), I-580, and I-680. Because MM 4.J-5c refers to traffic noise only, the model only considered roadways and did not consider sound from other sources such as stationary sources or rail lines. For local roads, Ldn data used in the model was based on Table 4.J-7 of the Draft SEIR, which provides cumulative 2035 data that includes estimated sound level increases from rezoning the Project site and other potential housing sites. In addition, the results of the project traffic noise impact study completed by Kimley-Horn were compared to the SEIR estimated sound level increases. The traffic sound levels in the SEIR were more conservative and, therefore, were utilized in the assessment. To our knowledge, no Ldn data for I-580 and I-680 within Pleasanton is publicly available. As a result, we based the sound levels for I-580 and I-680 on Caltrans 2019 traffic counts, including traffic counts for trucks. It is not clear what long-term effects the COVID-19 pandemic will have on traffic counts on highways such as I-580 and I-680. The model assumes that traffic counts will return to, but not exceed, 2019 traffic counts. The data provided by Caltrans includes peak monthly Average Daily Traffic (ADT) and peak hourly ADT. The data does not include daytime and nighttime traffic counts. To calculate the Ldn for each highway, it was assumed 80% of the peak hourly traffic to represent daytime traffic and 80% of