This map shows modeled outdoor noise across 94531 at 100-meter resolution, combining road, aviation, and rail sources. Green areas measure below 45 dBA. Orange and red exceed the EPA's 55 dBA outdoor threshold linked to long-term health effects. Use the layer toggles to view each source on its own or all together.
What the numbers sound like
- 30 dBAWhisper
- 40 dBASoft rainfall
- 45 dBAQuiet suburban street at night
- 50 dBAQuiet office
- 55 dBAEPA outdoor threshold: light traffic 100 ft away
- 60 dBANormal conversation an arm's length away
- 65 dBABusy restaurant
- 70 dBAHighway traffic 50 ft away
- 80 dBACity bus interior
Population Above the EPA Outdoor Threshold
The EPA's 55 dBA outdoor reference level is a common benchmark for residential noise exposure, especially for activity interference, annoyance, and long-term community noise concerns. About 12,112 94531 residents, or 29.2%, live above that level. By land area, 35.2% of 94531 is above 55 dBA.
See how noise in 94531 compares to similar-sized zip codes.
Noise by Part of 94531
Average noise levels for 94531 residents, grouped by direction from the center of 94531. Central 94531 carries the highest population-weighted average; Southern 94531 carries the lowest. Just 24% of residents in Southern 94531 live in blocks above the EPA's 55 dBA threshold, roughly the same as the share in Central 94531.
Central 94531
26% of people above 55 dBA
Eastern 94531
32% of people above 55 dBA
Northern 94531
33% of people above 55 dBA
Southern 94531
24% of people above 55 dBA
Western 94531
26% of people above 55 dBA
Central 94531 sounds about 34% louder than Southern 94531 to the human ear, a 4.2 dBA gap. Every 10 dBA roughly doubles perceived loudness. Within any of these directions, two homes a quarter mile apart can still differ by 10 or more dBA depending on how close they sit to a major highway.
How far back from State Rte 4 do you need to be?
State Rte 4 produces an estimated 77 dBA at its loudest centerline points. Noise drops logarithmically with distance, with the exact rate depending on what's between you and the road. Tree cover, walls, terrain, and pavement type all matter. At roughly a quarter mile back, traffic fades into the noise level of a quiet suburban street at night.
Calculated from the model's calibrated attenuation formula. About 4% of 94531 sits under tree canopy (much lighter than most zip codes) and roughly 45% is impervious surface like pavement and rooftops. Both are folded into the per-place decay rate above. Heavier canopy pulls noise down faster with distance; impervious surfaces slow the drop.