Interpretation and Geographic Equity Analysis
The Decibel (dB) is a unit of measurement used to quantify the intensity or magnitude of sound. A 10 dB change is generally perceived by the human ear as a doubling of noise. The LDN (Level Day/Night) noise level averages the daytime and nighttime noise levels (logarithmically) over a 24-hour period and includes a 10 dB (penalty) added to the nighttime noise level (10 pm to 7 am). This indicator measures the percent of the population living in an area with a LDN of greater than 60dB.
Overall, 70% of San Francisco’s population lives in an area with a traffic noise LDN of greater than 60dB. The Downtown/Civic Center, Western Addition, Financial Distric, Haight Ashbury, South of Market, Mission Bay, and Nob Hill neighborhoods all have more than 90% of their populations living in areas with high noise levels. The Seacliff, Treasure Island, Outer Sunset, and Outer Richmond neighborhoods have the lowest percentages of their populations living in high noise areas, all below 30%.
The Traffic Noise Model assists with implementation of the State Building Code requirements for acoustical insulation of new residential construction. The San Francisco Noise Model results can also help community groups advocate for sound walls, less mechanical equipment, less trucks, and quieter buses.
The San Francisco Noise Control Ordinance, Article 29, San Francisco Police Code provides an acoustical safety net for those noise sources that cannot be minimized through informed planning. It is an unfortunate fact of urban life that oftentimes what is seen as progress and development results in the degradation of the acoustical environment. Increasing truck and automobile traffic elevates the ambient street noise, while expanded use of air conditioning invades the quiet of neighborhood backyard. The rear yards of San Francisco often function as acoustical sanctuaries from the urban turmoil. It is important to protect them from the intrusion of new and unnecessary noise sources.
Seto, Holt and Rivard. University of California, Berkeley and SF Department of Public Health, Environmental Health Section. Traffic Induced Noise: Developing Analytic Tools for Assessing the Impacts of Transportation Policy on Environmental Health.
Map prepared by City and County of San Francisco, Department of Public Health, Environmental Health Section using ArcGIS software.
Table data is presented by planning neighborhood.
Detailed information regarding census data and other technical notes can be found at the following link: