Frequently asked questions
Modeled estimates for general information only — not measurements, not a guarantee, and not for legal, medical or real-estate decisions.
Short answers about the Quiet LA noise map. Each answer restates what Limits, How it’s made and Sources & methods say.
What is Quiet LA?
Quiet LA is a free noise map for Los Angeles County. It shows modeled outdoor noise from roads, trains and aircraft for day, evening and night, plus a 24-hour CNEL value. It is an independent project, not run or endorsed by any government agency, airline, airport or real-estate company.
Is the noise map measured?
No. Every number is a modeled estimate from a computer calculation, not a reading from a microphone. We compared the model with 564 public measurements around the county to check it. See How it’s made and Limits.
How accurate is the map?
At a single address the estimate is typically about 6 dB off, higher or lower, so a difference of a few dB between two addresses is within that error. On average the model is within about 0.5 dB of public 24-hour measurements, but near freeways it runs about 4 dB loud on average, with a wide spread. The aircraft estimate is within about 3 dB on average of 57 permanent airport monitors, and it reads low far out along some approach paths. Limits has the details.
What does “modeled” mean?
Modeled means calculated, not measured. For every street the model takes traffic volume, speed and truck share, then works out how the sound spreads over the ground, around buildings and past freeway sound walls. Where no traffic count exists it uses typical values for that kind of road. Sources & methods lists every data source.
What do Day, Evening, Night and 24 h CNEL mean?
Day is 7 am to 7 pm, Evening 7 to 10 pm and Night 10 pm to 7 am; each is an average sound level (LAeq) for that period. The 24 h value is CNEL, which averages the whole day while counting evening 5 dB and night 10 dB higher than day, and only this view includes aircraft, as an estimate derived from official airport contours. What 45, 55, 65 dB mean explains the numbers.
What is the difference between day and night levels?
Day and night levels differ because the model uses different traffic and weather assumptions for each period. Evening traffic is set at 0.6 times, and night at 0.2 times, the daytime flow, and sound is assumed to carry farther in the evening and at night than in the day. Aircraft appear only in the 24 h view, not in Day, Evening or Night.
Can I use this for a real-estate decision?
No. Quiet LA is not for legal, regulatory, appraisal or real-estate disclosure use, and it makes no claim about any home’s value, safety or livability. It does not replace official airport disclosure notices, environmental reviews or a professional acoustic survey. Check anything that matters to you with a professional or an on-site visit, and see Limits.
Does it cover my city?
Quiet LA covers Los Angeles County, both inside and outside the City of Los Angeles, and not other counties. Parks, mountains and desert get a coarse estimate from freeways and major roads only; land with no freeway or major road within 3 km shows the lowest color, which is an assumption, not a computed value. Other blank areas are not modeled yet, and blank never means quiet. Search your address on the map to see what is modeled there.
Does the map show LAX and aircraft noise?
Yes, in the 24 h view only. The aircraft level is an estimate derived from official airport contours, extended down to 55 CNEL where official maps stop at 65, and added to the road and train levels. It does not count individual flights, and you can switch Aircraft off to remove it from the 24 h value. See LAX and aircraft noise in Los Angeles.
Does it show helicopters, construction or nightlife?
No. Construction, events, nightlife, neighbors, helicopters and individual overflights are not modeled yet, and sirens, car horns and wildlife are not modeled either. A low modeled level does not promise a quiet night. For official contacts, see Who to call about noise in Los Angeles.
Are the levels indoors or outdoors?
Outdoors. Day, Evening and Night values are taken at a point 4 m up and 2 m out from a building wall, or 1.5 m above open ground. For buildings the map shows the loudest wall, and the panel also shows the least exposed wall. Windows, floors and insulation change what you hear inside, and the map does not model indoor sound.
Can I find quiet neighborhoods or quiet places to live in Los Angeles?
Quiet LA describes modeled noise from roads, trains and aircraft at specific places. It does not rate, rank or label neighborhoods, and it says nothing about who lives there. To compare options, look up the specific addresses or blocks you are considering and see which noise sources affect each one, keeping in mind that a few dB between two addresses is within the model’s error. The address guide shows how.
How do I look up the noise level at an address?
Open the map, type the address in the search box and choose the match; the map jumps to that building. Click the building to see its modeled Day, Evening, Night and 24 h levels at the loudest wall. The step-by-step guide explains each view.
Who do I call about a noise problem?
It depends on the source and on where you live. In the City of Los Angeles, loud parties go to the LAPD non-emergency line, 877-ASK-LAPD, and early or late construction goes to the LAPD Noise Enforcement Team. Aircraft, helicopters, freeway sound walls and unincorporated LA County each have their own contacts, listed with links in Who to call about noise in Los Angeles.
Is Quiet LA free, and does it store my address?
Quiet LA is free to use, with no account and no ads. When you search an address, your browser asks LA County’s public GIS service for it; we do not receive, store or log the address. See Privacy for what the site does and does not collect.