Healthy Development Measurement Toolkit

Indicator ST.2.a Proportion of commute trips made by public transit

Data Source

U.S. Census 2000, Geolytics software. Census variables used: ‘Proportion of population working outside the home who travel to work on public transportation' (TRVLPB0).

Map data is presented at the level of the census tract. The map also includes planning neighborhood names, in the vicinity of their corresponding census tracts.

Table data is presented by planning neighborhood. Planning neighborhoods are larger geographic areas then census tracts. SF DPH used ArcGIS software and a 'centroids within' methodology to convert census tracts to geographic mean center points. We then assigned census tracts to planning neighborhoods based on the spatial location of those geographic mean center points and calculated the planning neighborhood totals for the table.

Detailed information regarding census data, geographic units of analysis, their definitions, and their boundaries can be found in the HDMT at the following links:

http://www.thehdmt.org/etc/Geographic_Units_of_Analysis.September_2009.pdf

http://www.thehdmt.org/data_map_methods.php

Explanation and Limitations

The decennial survey of the US Census asks Americans which mode (i.e., car, public transportation, walking) they usually use to get to work. "Usually use" is defined as the mode used on the most days in the previous week. "Public transit" is defined as bus, trolley, streetcar, subway, railroad, commuter train, or ferryboat.

Lower income communities tend to rely more heavily on public transportation than higher income communities. Modes of transportation used to access work are dependent upon numerous variables. Among many others, these may include cost, distance, accessibility, perceived and actual safety, weather, pedestrian safety, traffic patterns, availability of bicycle lanes, hours of operation, availability of parking, and availability of travel stipends/incentives provided by work or to low income families.

Why is this a Community Health Indicator?

Using public transit helps people meet minimum requirements for physical activity. Twenty-nine percent of people using transit to get to work meet their daily requirements for physical activity from walking to work.^a 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.^b Relative to personal vehicles, transit trips contribute less to greenhouse gas and air pollution emissions.