This map shows modeled outdoor noise across Granite Bay 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 3,424 Granite Bay residents, or 16.9%, live above that level. By land area, 18.9% of Granite Bay is above 55 dBA.
See how noise in Granite Bay compares to similar-sized cities.
Noise by Part of Granite Bay
Average noise levels for Granite Bay residents, grouped by direction from the center of Granite Bay. The highest population-weighted average is in southeastern Granite Bay; the lowest is in northeastern Granite Bay, where just 8% of residents live in blocks above the EPA's 55 dBA threshold, three-quarters of the share in the loudest section.
Southeastern Granite Bay
12% of people above 55 dBA
Eastern Granite Bay
13% of people above 55 dBA
Southern Granite Bay
12% of people above 55 dBA
Northern Granite Bay
9% of people above 55 dBA
Northeastern Granite Bay
8% of people above 55 dBA
To the human ear, noise in southeastern Granite Bay sounds about 46% louder than in northeastern Granite Bay, a 5.5 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 do you need to be?
produces an estimated 73 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 soft rainfall.
Calculated from the model's calibrated attenuation formula. About 18% of Granite Bay sits under tree canopy (lighter than most cities) and roughly 34% 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.