Mapping San Francisco’s Most Speeding-Plagued Streets

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Urban cartographer Stephanie May used engineering and traffic surveys collected by the SFMTA between 2004 and 2010 to piece together this map of speeding. The darker the segment, the higher the average speed. Fatter segments represent streets with a higher incidence of speeding.

A new online map begins to show which San Francisco streets have the worst speeding problems, according to data from SFMTA engineering and traffic surveys. The map was created by Stephanie May, who works for the SF-based organization Urban Mapping and teaches cartography at SF State University and history at Stanford, according to her Twitter page.

Ideally, a map like this could show people where they should advocate for safety improvements, and where city agencies ought to focus enforcement and traffic calming efforts. This map is a start, but the available data has a lot of gaps, since speed surveys are typically done only in response to complaints from residents, May said. The data is also a bit dated, collected between 2004 and 2010. It would be interesting to see how road diets and other traffic calming measures implemented since then have changed the picture.

On Twitter, May said she thinks “the real message of the map is that @sfgov needs to monitor traffic speeds more systematically (and report).”