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.
Overall
Road
Rail
Aviation
Click the map to explore
35 dBa55 dBa (EPA limit)90+ dBa
3545557090
Quietest (dBA)Loudest
Colorblind friendlyoff
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.
Average noise levels for Friendly Acres residents, grouped by direction from the center of Friendly Acres. Northern Friendly Acres carries the highest population-weighted average; Western Friendly Acres carries the lowest. Just 24% of residents in Western Friendly Acres live in blocks above the EPA's 55 dBA threshold, a third of the share in Northern Friendly Acres.
Central Friendly Acres
56.7 dBA · Moderate-loud
Normal conversation an arm’s length away
57% of people above 55 dBA
QuietLoud
Eastern Friendly Acres
59.4 dBA · Loud
Normal conversation an arm’s length away
70% of people above 55 dBA
QuietLoud
Northern Friendly Acres
61.2 dBA · Loud
Busy restaurant
100% of people above 55 dBA
QuietLoud
Western Friendly Acres
52.3 dBA · Moderate
Quiet office to normal conversation
24% of people above 55 dBA
QuietLoud
Northern Friendly Acres sounds about 85% louder than Western Friendly Acres to the human ear, a 8.9 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.
Sources & Methodology
The BestNeighborhood noise model is calibrated against nearly one million federal ground-truth measurements across four states. Road noise is computed from segment-level federal traffic data and propagated outward using physics-based acoustic decay, with attenuation rates that depend on the surrounding land cover.
All inputs are published federal datasets. Block-level noise is computed by combining road, rail, and aviation sound sources in the energy domain, the same physics used in professional environmental noise assessments. Read the full methodology.
