Traffic Density

What is Traffic Density?

California has the biggest network of freeways in the country. Its cities are known for heavy traffic. Traffic density is a measure of the number of vehicles on the roads in an area. Non-whites, Latinos, low income people, and people who speak a language other than English often live in or near areas with high traffic.


Why is this indicator included in CalEnviroScreen?

  • While California has strict vehicle-emissions standards, exhaust from cars and trucks is the main source of air pollution in much of the state.
  • Major roads and highways can bring air pollutants and noise into nearby neighborhoods.
  • Exhaust fumes contain toxic chemicals that can damage DNA, cause cancer, make breathing difficult, and cause low weight and premature births.
  • Children who live or go to schools near busy roads have higher rates of asthma and other lung diseases than children in areas farther from roads.


What measure is used in CalEnviroScreen 3.0 to evaluate traffic density?

  • The indicator uses information on the amount of traffic on major as well as some local roads and the length of the roads in or near each census tract.
  • Traffic density is calculated by dividing the traffic volumes by the total road length for the year 2013.
  • A complete description of the Traffic Density indicator can be found in the CalEnviroScreen 3.0 report.


Where can I find more information about traffic and health?

CalEnviroScreen 3.0 Traffic Density Map

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