Healthy Development Measurement Toolkit

Indicator ST.3.a Ratio of miles of bike lanes and paths to miles of road

Data Source

Bike network data in the above map provided by the San Francisco Municipal Transportation Agency's Bicycle Program in May 2008, and includes bike routes formally adopted in the General Plan. A  map that also includes proposed near- and long-term improvements can be accessed online on at: http://www.sfmta.com/cms/bproj/documents/EIR_Map_PublicVersion_BW_85x11_February2008Update.pdf

Miles of bike lanes and paths data in the table taken from 2008 data released by the San Francisco Municipal Transportation Agency's Bike Program. Accessed online on May 28, 2008 at: http://www.sfmta.com/cms/bcomm/3180.html

Road miles taken from the 2007 San Francisco Municipal Transportation Agency's "San Francisco Transportation Fact Sheet." Accessed online on May 28, 2008 at: http://www.sfmta.com/cms/ains/documents/linkedFactSheet07Aug2.pdf

Explanation and Limitations

Bike paths, or Class I bikeways, are facilities with exclusive right of way, with cross flows by motorists minimized. Bike paths offer travel opportunities not provided by the road system, and are commonly created along ocean fronts, within college campuses, or within and between parks. Bike lanes, or Class II bikeways, provide a striped lane for one-way bike travel in the same direction as motor vehicle traffic on a street or highway. Bike lanes delineate the right of way assigned to bicyclists. Bike routes, or Class III bikeways, are established by placing Bike Route signs along roadways and provide for shared use with pedestrian or motor vehicle traffic. Additional information regarding these definitions and design specifications can be accessed in the California Highway Design Manual Chapter on Bikeway Planning and Design (available at: http://www.sfmta.com/cms/uploadedfiles/dpt/bike/HDM_1000.pdf).

The miles of bike lanes and paths are the approximate length of the network and not the actual number of miles of bicycle facilities (i.e., a two-way street with bike lanes in each direction and a one-way street with a bike lane in one direction are counted the same). As noted by the SF Bicycle Program, the number of miles of bike paths and bike lanes does not include the miles of signed bicycle routes (79 miles), miles of wide curb lanes (53 miles) or other dirt paths (8 miles). If these figures are included, there are 208 miles of bicycle accessible areas in San Francisco (http://www.sfmta.com/cms/bcomm/3180.html). It is notable that barriers to continuity of the bike network, e.g, road blocks or other physical barriers on the route, are not portrayed on the map. Road miles reported include public (including unaccepted), park, and military streets, freeways and freeway ramps, and exclude private streets.

Why is this a Community Health Indicator?

Bike paths and clearly delineated bike lanes can enable bicycle use and potentially decrease the number of bicyclist and pedestrian injuries. Biking can help people meet minimum requirements for physical activity. Health benefits of physical activity include a reduced risk of premature mortality and reduced risks of coronary heart disease, hypertension, colon cancer, and diabetes mellitus.^a Regular participation in physical activity also appears to reduce depression and anxiety, improve mood, and enhance ability to perform daily tasks throughout the life span. As a non-vehicle form of transport, bike trips do not contribute to noise or air pollution emissions.