How loud is Los Angeles County? The modeled figures
Updated
Modeled estimates for general information only — not measurements, not a guarantee, and not for legal, medical or real-estate decisions.
Across 16,597,837 modeled building-façade points in Los Angeles County, the median 24-hour level is 56.1 dB CNEL and the median at night is 47.5 dB. Road traffic is the largest modeled contribution at 96.1% of points. These are modeled estimates, not measurements, typically about 6 dB off at one spot (map data release of 14 October 2026).
Open Los Angeles County on the map
What are the modeled noise figures for Los Angeles County?
Every figure below is a modeled estimate for the county as a whole, taken at points on building façades, 4 m up and 2 m out from a wall. They count buildings of every kind, not homes, and they say nothing about any one area. Figures from the map data release of 14 October 2026, 14:09 UTC. The same figures appear as the county reference on every area page.
| Figure | Value (modeled) |
|---|---|
| Median | 56.1 dB |
| 1 point in 10 is below | 45.8 dB |
| 1 point in 10 is above | 68.0 dB |
| Points at or above 55 dB | 54.8% |
| Points at or above 60 dB | 34.1% |
| Points at or above 65 dB | 17.3% |
| Figure | Value (modeled) |
|---|---|
| Median | 47.5 dB |
| 1 point in 10 is below | 37.5 dB |
| 1 point in 10 is above | 59.8 dB |
| Points at or above 45 dB | 62.0% |
| Points at or above 50 dB | 39.6% |
| Points at or above 55 dB | 22.1% |
The 24-hour CNEL includes aircraft; the Night level does not. “1 point in 10 is below” and “1 point in 10 is above” are the 10th and 90th percentiles, so eight points in ten lie between them.
Which noise source is largest across the county?
At 96.1% of the modeled building-façade points, road traffic is the largest modeled contribution to the 24-hour level; rail is the largest at 0.6% and aircraft at 3.3%. Sirens are an optional layer and are not in these figures. These are shares of points in a model, not shares of all the sound anyone hears. See freeway and road noise, train and rail noise and airport noise.
How were the figures made and checked?
Quiet LA runs a computer model, NoiseModelling 6 with the CNOSSOS-EU method, on public data: traffic counts, building outlines, terrain, train schedules and the official airport contours. It was compared with 564 public measurements around the county; about 160 had a 24-hour value and a usable map position, and on average the model is within about 0.5 dB of them for the 24-hour level. At a single spot the estimate is typically about 6 dB off, higher or lower. The method is on How it’s made and every data source is named on Sources & methods; the datasets behind the model are linked below, named as that page names them.
How loud is that in everyday terms?
On Caltrans’ chart of typical outdoor sounds a quiet urban night is about 40 dB, a quiet urban day about 50 dB, heavy traffic at 300 feet about 60 dB and a commercial area about 65 dB. A CNEL is a 24-hour average with evening and night counted heavier, so it is not a sound you hear all day. See what 45, 55 and 65 dB mean, what CNEL means and Limits.
How do I cite these figures?
Quiet LA, “How loud is Los Angeles County? The modeled figures”, quietlamap.com/guides/how-loud-is-los-angeles/. Figures are modeled estimates from the map data release of 14 October 2026. Say “modeled” whenever you quote a figure; none is a measurement.
Open this on the map
- Los Angeles County over 24 hours (the CNEL view)
- Los Angeles County at night (the Night view)
Common questions
How loud is Los Angeles?
Across 16,597,837 modeled building-façade points in the county the median 24-hour level is 56.1 dB CNEL and the median at night is 47.5 dB. These are modeled, not measured.
What is the average noise level in Los Angeles?
Quiet LA publishes medians, not averages: 56.1 dB CNEL over 24 hours and 47.5 dB at night, for the map data release of 14 October 2026.
What is the biggest source of noise in Los Angeles?
In the model, road traffic is the largest contribution to the 24-hour level at 96.1% of building-façade points.
Are these figures measurements?
No. They are modeled estimates, compared with 564 public measurements, and typically about 6 dB off at one spot.
Sources
- NoiseModelling 6.0.0 (noise engine) Université Gustave Eiffel / CNRS (Noise-Planet). Run with scripts written for Quiet LA.
- CNOSSOS-EU common noise assessment methods (Commission Directive (EU) 2015/996) European Commission. The method NoiseModelling implements for road, rail and aircraft noise.
- Caltrans Traffic Volumes AADT (State Highway System count points, LA County) California Department of Transportation. One of the traffic count sources.
- FHWA Highway Performance Monitoring System (HPMS) 2024 Spatial All Sections, Los Angeles County rows U.S. Department of Transportation, Federal Highway Administration. Traffic counts for roads without a local count.
- LA County Building Footprints (DPW MapServer layer 0) County of Los Angeles Department of Public Works. The building outlines the points sit on.
- USGS 3DEP lidar point clouds (EPT) CA_LosAngeles_1_B23 U.S. Geological Survey 3D Elevation Program. Terrain and sound walls the lidar detected.
- Metrolink GTFS static feed and Amtrak GTFS static feed Published train schedules for the modeled Valley main lines.
- LAWA quarterly noise reports and maps for LAX and Van Nuys Los Angeles World Airports. One of the sources of the official airport contours the aircraft estimate starts from.