Noise Levels in Friendly Acres, Redwood City, CA | Find Quiet Neighborhoods With Our Sound Map
57 dBA
Average noise across Friendly Acres
Normal conversation an arm’s length away
2,531
Residents above the EPA 55 dBA threshold
55% of Friendly Acres residents
75 dBA
Loudest residential point
City bus interior
This map shows modeled outdoor noise across Friendly Acres 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 2,531 Friendly Acres residents, or 55.0%, live above that level. By land area, 50.4% of Friendly Acres is above 55 dBA.
49.6% below 55 dBA
50.4% above 55 dBA
See how noise in Friendly Acres compares to similar-sized neighborhoods.
Noise by Part of Friendly Acres
Average noise levels for Friendly Acres residents, grouped by direction from the center of Friendly Acres. The highest population-weighted average is in eastern Friendly Acres; the lowest is in western Friendly Acres, where just 40% of residents live in blocks above the EPA's 55 dBA threshold, about two-thirds of the share in the loudest section.
Eastern Friendly Acres
63.0 dBA · Loud
Busy restaurant
Central Friendly Acres
58.3 dBA · Loud
Normal conversation an arm’s length away
Western Friendly Acres
54.4 dBA · Moderate-loud
Quiet office to normal conversation
To the human ear, noise in eastern Friendly Acres sounds about 82% louder than in western Friendly Acres, a 8.6 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 75 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.
At source
75 dBA
City bus interior
165 ft
61 dBA
Busy restaurant
330 ft
53 dBA
Quiet office to normal conversation
660 ft
45 dBA
Quiet suburban street at night
¼ mile
37 dBA
Soft rainfall
½ mile
35 dBA
Soft rainfall
Calculated from the model's calibrated attenuation formula. About 6% of Friendly Acres sits under tree canopy (lighter than most neighborhoods) and roughly 64% 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.
-->
Airport Noise
San Francisco International (SFO) sits northwest of Friendly Acres. The U.S. Department of Transportation measures aviation noise around this airport directly, and the model uses those federal measurements rather than synthetic predictions.
Blocks under the approach and departure paths carry combined road-plus-aviation noise, with some exceeding 75 dBA on the map's Overall layer. Blocks on the opposite side of Friendly Acres, particularly to the southeast, show no measurable aviation contribution. Use the Aviation toggle on the map above to isolate the airport's footprint.
How Noise Is Distributed Across Friendly Acres
The bar chart below shows the share of Friendly Acres residents in each noise band. About 46% of residents live below the EPA's 55 dBA threshold, and roughly 20% live in blocks above 60 dBA. Long-term exposure in that range is linked to elevated stress hormones and cardiovascular risk.
How Friendly Acres Compares
Friendly Acres sits at the quieter end of the spectrum. Below: how Friendly Acres's average outdoor noise and share of residents above the EPA threshold compare with Farm Hills, Belle Haven, Fair Oaks, and Shoreview.
Average noise level (dBA)
Friendly Acres's 56.7 dBA pop-weighted average is at the quieter end of the spectrum. California as a whole averages 54.0 dBA and the U.S. averages 52.0 dBA. Both are lower than Friendly Acres because most of either area is rural land away from major roads.
Share of residents above 55 dBA
About 55.0% of Friendly Acres residents live in blocks where outdoor levels exceed the EPA's 55 dBA threshold. That's in the middle of its peer group. Measured by land area instead, 50.4% of Friendly Acres's footprint sits above 55 dBA, against a California average of 36.0% and a national average of 28.1%.
What This Means if You're Moving to Friendly Acres
- Distance from highways matters more than the neighborhood name. Two homes in the same zip code can differ by 20 dBA if one sits 100 meters from and the other 500 meters away. The model captures this at 100-meter resolution, so noise exposure changes block by block.
- Tree canopy can help reduce modeled noise exposure. Roughly 6% of Friendly Acres is under tree cover (lighter than most neighborhoods), and the dominant land cover is medium-intensity developed land. Both are measured from federal USDA Forest Service and USGS satellite imagery at 30-meter resolution. Streets with 60% or higher canopy show 3 to 5 dBA lower noise than comparable streets with bare ground or pavement, which is why the per-place decay rate above already accounts for it.
- Airport noise is directional. San Francisco International's approach paths concentrate aviation noise to the northwest. Neighborhoods to the southeast of downtown show no measurable contribution from the airport.
