Traffic noise map of Los Angeles

Updated 23 October 2026

Modeled estimates for general information only — not measurements, not a guarantee, and not for legal, medical or real-estate decisions.

Quiet LA is a traffic noise map of Los Angeles County. It models road noise from traffic counts, vehicle speed and truck share on every street, then spreads the sound over the ground, around buildings and past freeway sound walls. Open it for any freeway or street, or start from a freeway guide below. The levels are estimates, not measurements.

Open the traffic noise map

What is a traffic noise map, or a highway noise map?

A traffic noise map, sometimes called a highway noise map, shows how loud the traffic on roads and freeways is at places nearby. It is almost always modeled: the sound is calculated from how many vehicles pass, how fast and how many are trucks, because no one can measure every street. Quiet LA’s map is modeled in this way. Its numbers are outdoor levels at building walls, not what you hear inside.

On the map, road noise is in the colors of every view. Day, Evening, Night and the 24 h value (CNEL) all include it, and the 24 h view can add an aircraft estimate. For the full picture of layers, see the noise pollution map guide.

Which freeway noise guides does Quiet LA have?

Each guide covers one freeway: the cities and communities it runs through, the airports and rail lines it meets, and the modeled levels at building façades by distance from it. The list is in route-number order and says nothing about which freeway is louder.

For streets and freeways in general, how traffic, trucks, sound walls and weather change the level is in freeway and road noise in Los Angeles.

How does traffic noise change with traffic and distance?

Caltrans’ Technical Noise Supplement gives the basics. Vehicle noise grows with speed, and it takes a doubling of traffic to raise the level by 3 dB, which is barely noticeable. Traffic acts as a line of sound, so with distance from a road the level drops by 3 dB for each doubling of distance from spreading alone, and more over soft ground. Hills, buildings and noise barriers change that.

The freeway guides show the same pattern in the Quiet LA data: the median level at building façades in four distance bands, within 100 m, 100 to 250 m, 250 to 500 m and 500 m to 1 km of the freeway. The tables use all modeled sources at those buildings, not the freeway alone, and they are not compared between freeways.

How does Quiet LA model road noise?

• It starts from public traffic counts for each road. Where no count exists it uses typical values for that kind of road.
• It takes evening traffic as 0.6 times and night traffic as 0.2 times the day flow.
• The detailed model looks 1.5 km out from each road. A coarser calculation of freeways and major roads out to 8 km, reduced for the buildings in between, is added to the map colors, not to the value for a single address.
• Sound walls the lidar detected, buildings and hills are in the model; walls it did not detect are not.
• 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; that is an assumption, not a computed value.

At a single address the estimate is typically about 6 dB off, and near freeways the model runs about 4 dB loud on average. See How it’s made, Sources & methods and Limits.

What does a traffic noise map not show?

• Today’s traffic, a crash or a closed lane. The levels are typical patterns for a period, not an observation of a day.
• Car horns, motorcycles or one loud vehicle, and sound inside buildings.
• Whether a freeway meets any rule. A map level is not a compliance test.

Who handles freeway and road noise?

Contact checked against the Caltrans page on 21 October 2026. Phone numbers change, so confirm on the agency page before you call.

Caltrans runs the state highways, and its District 7 office covers Los Angeles at (213) 897-1200. For a new sound wall along an existing freeway, Caltrans says that since January 1998 sponsoring these retrofit projects belongs to local transportation agencies. See who to call about noise in Los Angeles for the rest.