This map shows modeled outdoor noise across 28449 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 601 28449 residents, or 37.8%, live above that level. By land area, 38.6% of 28449 is above 55 dBA.
See how noise in 28449 compares to similar-sized zip codes.
Noise by Part of 28449
Average noise levels for 28449 residents, grouped by direction from the center of 28449. The highest population-weighted average is in central 28449; the lowest is in southern 28449, where just 4% of residents live in blocks above the EPA's 55 dBA threshold, a fifth of the share in the loudest section.
Central 28449
25% of people above 55 dBA
Northern 28449
18% of people above 55 dBA
Southern 28449
4% of people above 55 dBA
To the human ear, noise in central 28449 sounds about 54% louder than in southern 28449, a 6.2 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 US-421 do you need to be?
US-421 produces an estimated 62 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 10% of 28449 sits under tree canopy (lighter than most zip codes) and roughly 51% 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.