This map shows modeled outdoor noise across Johnson Ranch 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 678 Johnson Ranch residents, or 21.4%, live above that level. By land area, 25.2% of Johnson Ranch is above 55 dBA.
See how noise in Johnson Ranch compares to similar-sized neighborhoods.
Noise by Part of Johnson Ranch
Average noise levels for Johnson Ranch residents, grouped by direction from the center of Johnson Ranch. Central Johnson Ranch carries the highest population-weighted average; Northern Johnson Ranch carries the lowest. Just 9% of residents in Northern Johnson Ranch live in blocks above the EPA's 55 dBA threshold, a third of the share in Central Johnson Ranch.
Central Johnson Ranch
34% of people above 55 dBA
Eastern Johnson Ranch
33% of people above 55 dBA
Northern Johnson Ranch
9% of people above 55 dBA
Southern Johnson Ranch
26% of people above 55 dBA
Western Johnson Ranch
22% of people above 55 dBA
Central Johnson Ranch sounds about 15% louder than Northern Johnson Ranch to the human ear, a 2.0 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 71 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 17% of Johnson Ranch sits under tree canopy (about average for neighborhoods) and roughly 48% 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.