101 freeway noise in Los Angeles
Updated
Modeled estimates for general information only — not measurements, not a guarantee, and not for legal, medical or real-estate decisions.
The 101 is the Hollywood Freeway through downtown and Cahuenga Pass and the Ventura Freeway across the San Fernando Valley. In the Quiet LA map data it runs from downtown Los Angeles west through Hollywood, Studio City and Woodland Hills to Agoura Hills and Westlake Village. This page shows where it runs, which airports and rail lines it meets, and what the model says about the level at buildings at different distances from it.
Where the 101 runs
In the map’s road data, U.S. Route 101 (Hollywood and Ventura Freeways) is about 62 km long inside the area the map covers. It runs through 3 cities and communities and 18 City of Los Angeles Neighborhood Council areas. An area is listed when at least half a kilometer of the freeway lies inside its boundary; the lists are alphabetical, and being on one says nothing about how loud an area is.
Cities and communities: Agoura Hills, Calabasas, Westlake Village.
Neighborhood Council areas in the City of Los Angeles: Arts District Little Tokyo, Boyle Heights, Downtown Los Angeles, East Hollywood, Echo Park, Encino, Greater Toluca Lake, Historic Cultural North, Hollywood Hills West, Hollywood Studio District, Hollywood United, Lake Balboa, Rampart Village, Sherman Oaks, Silver Lake, Studio City, Tarzana, Woodland Hills-Warner Center.
Airports and rail lines near the 101
Airport reference points within 5 km of the freeway, with the distance to its nearest part: Van Nuys Airport (VNY), 4.5 km.
The map adds its aircraft estimate, derived from official airport contours, to the 24 h value only, inside the estimated 55 CNEL line. Day, Evening and Night never include aircraft.
The map’s rail data crosses the freeway at: Metrolink Orange County Line in Arts District Little Tokyo (not in the rail model); Metrolink Riverside Line in Boyle Heights (not in the rail model). Only the San Fernando Valley main lines are in the rail model, so a train on any other line is not in these numbers. See train and rail noise.
Modeled levels by distance from the 101
Across 543,655 modeled building-façade points within 1 km of the 101, the median 24-hour level is 73.4 dB CNEL within 100 m of the freeway and 57.3 dB CNEL 500 m to 1 km. The figures are from the map data release of 15 October 2026, 17:53 UTC; the live map may show a different release.
| Distance from the freeway | Points | 1 in 10 below | Median | 1 in 10 above | Night median |
|---|---|---|---|---|---|
| 24-hour level (CNEL) and Night (10 pm–7 am, LAeq) | |||||
| within 100 m | 30,220 | 61.5 dB | 73.4 dB | 80.7 dB | 65.2 dB |
| 100 m to 250 m | 78,980 | 54.1 dB | 65.7 dB | 72.8 dB | 57.7 dB |
| 250 m to 500 m | 146,855 | 50.3 dB | 60.8 dB | 68.5 dB | 52.8 dB |
| 500 m to 1 km | 287,600 | 47.1 dB | 57.3 dB | 66.2 dB | 49.3 dB |
The points are building façades of every kind, 4 m up and 2 m out from the walls, not homes. They are modeled estimates, not measurements. At a single spot the model is typically about 6 dB off, and near freeways it runs about 4 dB loud on average, with a wide spread, so use the table for the shape of the drop with distance and not for any one building. Sound walls the lidar detected, buildings and hills are in the model; walls it did not detect are not. See Limits.
The model treats the 101 as it treats every road. See freeway and road noise in Los Angeles for traffic, trucks, sound walls and weather, How it’s made for the method and Limits for what the numbers cannot be used for.
Open this on the map
Each link opens the map at that place in the 24-hour view. Switch to Night in the panel for the night level, and select a building to read its modeled values. The legend at the right edge of the map explains the colors.
Common questions
How loud is the 101 freeway?
Quiet LA does not measure it; it models it. Within 100 m of the 101, the median modeled 24-hour level at building façades is 73.4 dB CNEL (1 point in 10 is below 61.5 dB and 1 in 10 above 80.7 dB), and the median Night level is 65.2 dB. A modeled number is an average over a period, not what one passing truck sounds like. See what 45, 55 and 65 dB mean.
How far does 101 freeway noise reach?
In the map data the median 24-hour level at building façades falls from 73.4 dB within 100 m of the 101 to 57.3 dB 500 m to 1 km, and the spread within each band is wide. In general acoustics, steady traffic loses about 3 dB each time the distance doubles, and the first row of buildings beside a highway typically shields the rows behind it by about 3 to 5 dB (Caltrans). See freeway and road noise.
Do sound walls reduce 101 freeway noise?
Where a barrier blocks the line of sight between the road and a listener, it lowers the level; Caltrans gives about 5 dB for a barrier whose top just reaches that line. The map includes the freeway sound walls it could detect in lidar and leaves out walls it did not detect and private walls, so a wall you can see may not be in the model. See who to call about noise in Los Angeles for how sound wall requests work.
Who do I contact about 101 freeway noise?
Caltrans runs the state highways, and its District 7 office covers Los Angeles; the Caltrans contact page lists (213) 897-1200. Quiet LA is a model and cannot say whether any rule is met. The full list of contacts is in who to call about noise in Los Angeles.
Sources
- Caltrans: Technical Noise Supplement to the Traffic Noise Analysis Protocol (September 2013) Spreading with distance (section 2.1.4), buildings as shields (page 2-35) and noise barriers (page 2-41).
- Caltrans: Contact Us District 7 (Los Angeles) contact details, checked 21 October 2026.
- Caltrans: Traffic Census Program Traffic and truck counts for the State Highway System, one of the count sources Quiet LA uses.