Background
Although Complete Streets interventions, which change street infrastructure to accommodate active transportation users, are popular, they are seldom evaluated for relationships with physical activity among area residents.

Objectives
We test whether physical activity (PA) increases and body mass index (BMI) measures decrease for those using a Complete Street intervention that extended a light rail line in Salt Lake City.

Methods
Residents living within 2km of the new line wore accelerometers and global positioning system (GPS) loggers for one week pre- and post-rail construction. Data were integrated so that we could discern who engaged in transit use when taking trips within the Complete Street corridor. The Complete Street intervention included five new residential TRAX stops along a new line extension (and a 6th non-residential stop at the airport), a bike path, and improved sidewalks. Participants completed surveys, had height and weight measures taken, and were fitted with the devices in their homes. Participants, typically recruited door-to-door, were selected to be over 18, able to walk a few blocks, intending to stay in the neighborhood ≥ 1 year, not pregnant, able to speak Spanish or English, and to wear the devices (at least 3 10-hour days) and fill out the surveys.  We use the subsample of 537 residents who had valid GPS data at both times.  GeoStats assigned trip modes to active travel and could identify walking, bus riding, and light rail riding.  Any trip that crossed into or through an area defined by a 40-meter buffer from street centerline, encompassing all five new residential TRAX stops, was counted as a trip that involved the new Complete Street.  The outcome variables include changes in accelerometer counts per minute (CPMs) and in measured BMI. An OLS regression estimated change in PA from Time 1 to Time 2 as a function of baseline measures of PA, plus socio-demographic control variables. A similar analysis was conducted on BMI change.  Effect code contrasts compared residents who never registered a transit trip that intersected the Complete Street buffer with the other three groups:  continuing riders, abandoned riders, and new riders.

Results
A test of the transit ridership groups shows significant changes in activity CPMs, F(10,517) = 13.67, p < .001.  Compared to those who never rode transit, those who abandoned using transit (from 2012 to 2013) experienced a decline in physical activity, t = -2.83 p = .005.  Compared to those who never rode transit, those who started to use transit in 2013 accrued more physical activity, t = 2.85, p = .005. The continuing transit riders did not experience much change in activity and their 2013 to 2102 change scores were not significantly different from those who never used transit.   Physical activity changes were consistent with BMI change scores (2013 BMI minus 2012 BMI).  Compared to those who never rode transit, those who abandoned using transit experienced an increase in measured BMI, t = 2.49, p = .013.  Compared to those who never rode transit, those who started riding transit had lower BMI change scores, which actually indicated a slight loss of BMI, t = -3.02, p < .003.

Conclusions
The Complete Street intervention demonstrated beneficial physical activity and BMI changes for new transit riders and detrimental changes for those who abandoned transit.  BMI changes were also significant and in the expected direction, despite the fact that the 2013 measures came after at most seven months after the new transit opportunities were provided.

Implications
Many endorse Complete Streets for their potential to support physical activity, obesity prevention, social equity, youth and elder mobility, pollution prevention, less automobile dependence and sprawl, open space preservation, and transit-oriented development. The current study underscores benefits to health conferred by transit use.

References

1. McCann B. Completing Our Streets: The Transition to Safe and Inclusive Transportation Networks. Island Press; 2013.
2. Litt JS, Reed HL, Tabak RG, et al. Active living collaboratives in the United States: Understanding characteristics, activities, and achievement of environmental and policy change. Preventing Chronic Disease. 2013;10(2).
3. Rissel C, Curac N, Greenaway M, Bauman A. Physical activity associated with public transport use-a review and modelling of potential benefits. International Journal of Environmental Research and Public Health. // 2012;9(7):2454-2478.
4. MacDonald JM, Stokes RJ,  Brown, B.B., Wilson, L., Tribby, C.P., Werner, C.M, Wolf, J., Miller, H.J., Smith, K.R. (2014).  Adding maps (GPS) to accelerometry data to improve study participants’ recall of physical activity: a methodological advance in physical activity research.  British Journal of Sports Medicine.  doi: 10.1136/bjsports-2014-093530.
5. Brown, B.B., & Werner, C.M. (2007). A new rail stop: Tracking moderate physical activity bouts and ridership. American Journal of Preventive Medicine, 33(4), 306-309.

Support / Funding Source
Research reported in this publication was supported (in part) by grant number CA157509 from the National Cancer Institute at the National Institutes of Health and the Robert Wood Johnson Foundation.