Palo Alto Plan reduces total noise for people on the ground

Palo Alto Plan will reduce total noise for people on the ground

We have been hearing that the plans proposed by the City of Palo Alto will “devastate” Mountain View and Sunnyvale. This is complete nonsense.

Here are two noise contours developed by Freytag and Associates using AEDT-2, the latest modeling software used by the FAA. The medium purple color represents area exposed to 45-50 dB DNL and the blue area represents 50-55 dB. The ambient level in suburban areas is ~45 dB. These contours assume that all of the northbound traffic will pass along these pathways. Since Palo Alto believes that the noise burden should be shared, Palo Alto will take some portion of the traffic. If half of the traffic is shunted through Palo Alto, the proposed SERFR-EDDYY noise will be ~3 dB lower.

serfr contour

The figure above is the contour for SERFR (current conditions). Notice that the blue area (50-55 dB) covers a small part of Los Altos, covers a wide swath through Palo alto then turns over the Bay.

Serfr Eddyy contour

This is the proposed SERFR-EDDYY route. Notice that the blue area is now entirely over water. The purple area is shifted very slightly to the southeast. Palo Alto still gets a sizable dose but the total noise dose exposed to people is reduced and the burden is shared. Again, since the traffic will be shared between the old and new paths, this figure probably overestimates the noise dose by approx. 3 dB.