Sustainable Communities Index

Indicator TR.1.c Time spent walking or biking

Why Is This An Indicator Of Health and Sustainability?

Evidence that physical activity has multiple health benefits is unequivocal.  A 2008 comprehensive review documents the particularly strong evidence for a causal relationship between activity level and enhanced cardiorespiratory and muscular fitness, cardiovascular and metabolic health biomarkers, bone health, body mass and composition in children and youth.  In adults and older adults, strong evidence demonstrates that, compared to less active counterparts, more active men and women have lower rates of all-cause mortality, coronary heart disease, high blood pressure, stroke, type 2 diabetes, metabolic syndrome, colon cancer, breast cancer, and depression.  For older adults, strong evidence indicates that being physically active is associated with higher levels of functional health, a lower risk of falling, and better cognitive function.  This research reported reasonably consistent findings specifically for the health benefits of walking – showing a consistently lower risk of all-cause mortality for those who walk 2 or more hours per week.^a  A 2011 report issued by an international group of experts of data from Copenhagen documents similar all-cause mortality benefits from regular cycling for commuting controlling for socio-demographic and leisure time physical activity.^b  While regular physical activity can help people lead longer, healthier lives, a 2009 summary by the Robert Wood Johnson Active Living Research program revealed that fewer than 50% of children and adolescents and fewer than 10% of adults in the U.S. achieve public health recommendations of 30 to 60 minutes per day of moderate- to vigorous-intensity physical activity on 5 or more days of the week recommendations.^c 

Walking or biking for utilitarian trips is an opportunity to incorporate routine physical activity into daily living.  There are multiple environmental barriers that both children and adults face to achieving recommended levels of physical activity, including: limited discretionary time; barriers to accessing parks and recreational areas; reductions in school physical education programs;  and sidewalks, streets, or outdoor spaces that are not or are not perceived as safe to use.   Encouraging and facilitating active transportation – walking or cycling as a form of travel for utilitarian trips – is a key strategy for increasing daily physical activity.^d  Built environmental factors that are associated with active transportation via walking and cycling include increased resident and employment density, greater diversity of land use mix (e.g., residential land use near retail land uses), shorter distances destinations, and street design factors (e.g., grid street networks, the presence of sidewalks).^e

Methods

Using SF CHAMP 4.3.0 data for 2011, the average walking distance in miles traveled by Transportation District was multiplied by 20, using an assumption of 3 mph for walking speed, to obtain an estimate of the time spent walking everyday.  A similar calculation was conducted for biking using 6 mph for bike speed, to estimate time spent biking daily.  The data were then mapped to San Francisco’s 12 Transportation Districts.  

Limitations

Data is from the SFCTA’s travel forecasting model, SF CHAMP 4.3.0 data.  While the model is internationally regarded as a sophisticated travel forecasting approach which provides the best available estimates, its outputs are not precise predictions and the district-level estimates presented in the above map and table have not been validated.