The key variable in traffic congestion -- and in numerous other factors that collectively determine our quality of life -- is VMT, or vehicle miles traveled. People travel in widely varying amounts, depending on a number of factors. The most important factor is population density. This map of Sonoma County shows how much the per capita annual vehicle miles vary according to density. In the map, zones are color coded according to average annual per capita VMT.



The zones are Sonoma County's portion of the Metropolitan Transportation Commission’s 1099 Travel Analysis Zones (TAZ), which cover the San Francisco metropolitan area. Figures for vehicle miles were obtained from odometer readings that come from the smog check program*.

*For further information see study by Holtzclaw.


To download this map in PDF format, click here.