Indicator ST.1.b Proportion of commute trips made by driving alone
Data Source
U.S. Census 2000, Geolytics software. Census variables used: ‘Workers 16+ years old traveling to work by car, truck, or van' (AUTO0) and ‘Workers 16+ years old working outside the home' (TRVLPB0D).
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.
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.
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. The above data includes people who reported they usually got to work using a "car, truck, or van" and that they "drove alone."
Modes of transportation used to access work are dependent upon numerous variables including 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?
Driving has numerous negative consequences for public health - including traffic contributions to degraded air quality, environmental noise, climate change, and motor vehicle injuries and deaths, as well as reduced opportunities for physical activity and its physical and mental health benefits.a
Driving time independently predicts obesity risk. A study on the driving habits of over 10,000 Atlanta residents found that each additional hour spent in the car was associated with a 6% increase in the likelihood of being obese.b
- Ewing R, Frank L, Kreutzer R. Understanding the Relationship between Public Health and the Built Environment: A Report to the LEED-ND Core Committee. 2006.
Frank LD, Andresen MA, Schmid TL. Obesity relationships with community design, physical activity, and time spent in cars. Am J Prev Med. 2004;27(2):87-96.