A Public Health Perspective on a Non-Subsidized Bike Share New York City s Citi Bike

Size: px

Start display at page:

Download "A Public Health Perspective on a Non-Subsidized Bike Share New York City s Citi Bike"

Jordan Cook
5 years ago
Views:

1 A Public Health Perspective on a Non-Subsidized Bike Share New York City s Citi Bike Lori Suzanne Schomp, MPH Candidate, Mailman School of Public Health, Columbia University American Public Health Association, Annual Meeting, Atlanta, Georgia Current Findings in Health Disparities in Public Health Epidemiology November 7, 2017

2 Presenter disclosure Lori Suzanne Schomp The following personal financial relationships with commercial interests relevant to this presentation existed during the past 12 months: No relationships to disclose.

3 Why bike shares and public health? Existing interventions to address pervasive physical inactivity in the US have met with only narrow success and little progress has been made. Chronic disease prevention strategies focus on behavior change, embedding physical activity into daily habits, active commuting is among these strategies. Health benefits from bicycle commuting have been well documented and include reduced risk for chronic disease, cardiovascular disease and cancer, obesity and diabetes, and all-cause mortality. Bike shares have been shown to promote bicycling by expanding bicycling opportunities both by facilitating commuting, one-way trips, and by normalizing bicycling, creating a virtuous cycle. Bike shares are growing rapidly; bike share trips between were estimated at 88 million, and 2016 trips represent 25% growth over the prior year. Notwithstanding the evidence for health effects from bicycle commuting, and bike share growth, the evidence for health effects from bike shares is equivocal. Background

4 Equivocal health impacts considerations Private bike share ownership may limit research; still, bike shares have not been linked to increases in population physical activity as assessed by federal, state, local or other public health surveillance findings. Alternatively, population health impacts may be smaller than expected because bike share trips commonly replace other active commute modes like walking, private bicycle or public transit, and less commonly, wholly sedentary transit modes such car or taxi. Yet another explanation, underdeveloped in bike share literature, is that bike share physical activity may be inconsequential because the participants are already highly active. Positive associations between physical activity engagement and socioeconomic status (SES) are well established. If bike share distributions are effected by SES, then bike share users might advantageously possess resources and opportunities to maintain and protect their health including high physical activity engagement and ample opportunities for physical activity. Interventions (like bike shares) implemented without attention to default socioeconomic conditions may perpetuate or exacerbate existing health inequalities. Background

5 Physical activity engagement and socioeconomic status 50% 45% 40% 35% 30% 25% 20% 15% 10% 5% 0% 50% 45% 40% 35% 30% 25% 20% 15% 10% 5% 0% Blackwell DL, Lucas JW, Clarke TC. Summary health statistics for U.S. adults: National Health Interview Survey, National Center for Health Statistics. Vital Health Stat 10(260) federal physical activity guidelines % 11.30% Medicaid under age 65 40% Poverty Status 34.20% Met both muscle-strengthening & aerobic guidelines (%) 16.80% 17.50% Black or African American 29.50% Female 20.70% 21.40% Total (ageadjusted) CDC BRFSS 500 Cities 2016 No Leisure Time Physical Activity (%) 26.40% 22.90% 24.10% 24.60% 29.50% White Large MSA $75k - $99K Male Bachelor's degree or higher 24.20% 22.10% 21.90% 31.00% $100k or greater 12.40% 12.30% Less than $15,000 $15,000 - $24,999 Non-Hispanic Black Female Total Non-Hispanic White Male $75,000 or greater College graduate

6 Bike share distribution by SES as a cause for equivocal health impacts Hypotheses Bike shares affected by SES create distribution inequities and, together with capped benefits for increases in physical activity, these inequities minimize bike share population health effects. Existing literature raises these factors, yet relatively little research has investigated these premises directly: Bike share distribution disparities by SES Bike share distribution associations with other physical activity opportunities and physical activity engagement Background

7 Our study We investigated New York City s bike share, Citi Bike. Citi Bike was founded as an unsubsidized public-private partnership and the bike share s distribution may reasonably be expected to reflect the city s default socioeconomic conditions. Bike share distribution was assessed at two levels: Access who has access to a bike share station? Participation given access, do these associations persist with trips? Socioeconomic status (SES) was operationalized as income, bachelor degree, racialized groups as a marker of ethnic advantage and disadvantage, and Medicaid enrollees. Other physical activity opportunities and engagement was assessed as walking and bicycle commutes and commute minutes, and participation in leisure time physical activity. Methods

9 Study design Design: Cross-sectional, ecological study, 2,167 census tracts utilized as proxy for neighborhoods Population: New York City s 8.4 million population Data: Citi Bike Share System Data Trip data from July 2013 to September 2017 U.S. Census Bureau American Community Survey (ACS) DP05 Demographic and Housing Estimates DP03 Selected Economic Characteristics S1501 Educational Attainment S0801 Commuting Characteristics S2704 Public Health Insurance Coverage by Type CDC 500 Cities: Local Data for Better Health, Behavioral Risk Factor Surveillance System No Leisure Time Physical Activity (No LTPA) Methods

10 Analyses Reliability of census tract socioeconomic data determined utilizing ACS population estimates coefficient of variation Citi Bike Share System Data, removed non-subscriber trips. Citi Bike subscribers largely live in neighborhoods with a Citi Bike station and this further guided our neighborhood study design choice Bike Share start station s longitude and latitude linked to census tract using Esri ArcGIS software Descriptive statistics Access to bike stations measured with polychoric correlations Bike share participation as trips per census tract measured with Pearson correlations and quintiles Methods

11 Initial findings Results

12 Initial findings Final census tracts/neighborhoods included n= 2,111 with 56 census tracts removed after being identified as having low population estimates reliability A growing number of bike station s longitude and latitude were linked to a growing number of census tracts during the study period (160 census tracts in 2013, 344 census tracts in 2017) Subscriber trips were 88% of total trips 42.6 million subscriber bike share trips occurred in the study s census tracts between July Sept 2017 Bike trips were growing; May Dec million trips and Jan-Sept million trips 75.5% of trips were by men, 50% of trips were by users age 35 and younger, 75% of trip durations were 15 minutes or shorter Results

13 No leisure time physical activity by census tract 2,111 study sample census tracts Results

14 Bike share trips over time by census tract no leisure time physical activity

15 Bike station trips by census tract income 42.6 million trips July 2013 to September bike stations Stations linked to 344 study sample census tracts Results

16 Access Bike stations Results

17 Bike share access - ethnic SES markers N White Black Other N White Black Other Access % 3.4% 7.6% % 11.1% 14.5% Non-Access 1, % 96.6% 92.4% 1, % 88.9% 85.5% Polychoric correlation Station N 2,111 2,111 2,111 2,111 2,111 2,111 ASE NYC s population 43% white, 24% black, 32% other In 2013 access population was 63% white, 9% black, 27% other. In 2017, access was largely unchanged 63% white, 14% black, 24% other. Results

18 Bike share access education, income, Medicaid SES markers N Bachelors Income Medicaid N Bachelors Income Medicaid Access % $76, % % $66, % Non-Access 1, % $28, % 1, % $25, % Polychoric correlation Station N 2,110 2,110 2,111 2,110 2,110 2,111 ASE NYC s population 24% Medicaid enrollees In 2013 access population was 11% Medicaid. In 2017, this increased to 13%. Results

19 Bike share access other physical activity opportunities and engagement N Commute Walk Bicycle No LTPA N Commute Walk Bicycle No LTPA Access % 2.7% 18.6% % 2.5% 20.7% Non-Access 1, % 0.8% 29.7% 1, % 0.6% 30.4% Polychoric correlation Station N 2,105 2,110 2,110 2,111 2,105 2,110 2,110 2,111 ASE NYC s citywide commute mean was 40.8 minutes, 9% walk, 0.9% bicycle and 28.8% No LTPA. Results

20 Participation Bike share trips Results

21 Bike share participation - ethnic SES markers White Trips Black Trips Other Trips White Trips Black Trips Other Trips Quintile 1 0.6% 15% 0.1% 24% 0.3% 21% 1.1% 11% 0.1% 21% 0.6% 15% Quintile 2 1.4% 12% 0.2% 25% 0.7% 15% 2.8% 13% 0.4% 28% 1.4% 20% Quintile 3 2.3% 21% 0.3% 23% 1.1% 21% 4.6% 21% 0.8% 26% 2.1% 19% Quintile 4 3.5% 22% 0.6% 19% 1.6% 21% 7.3% 25% 2.0% 19% 3.2% 23% Quintile 5 5.3% 29% 2.3% 9% 3.8% 22% 12.7% 30% 7.9% 6% 7.2% 23% 13.0% 100% 3.4% 100% 7.6% 100% 28.5% 100% 11.1% 100% 14.5% 100% Pearson correlation Trips N P-value <.0001 < <.0001 < In 2013, trips above citywide mean percent white, black and other were 63%, 4% and 32% In 2017, trips above citywide mean percent white, black and other were 78%, 6% and 30% Results

22 Bike share participation - education, income, Medicaid SES markers Quintile 1 Quintile 2 Quintile 3 Quintile 4 Quintile 5 Pearson correlation Bachelor Trips Income Trips Medicaid Trips Bachelor Trips Income Trips Medicaid Trips 0.8% 14% $24,264 8% 0.0% 26% 1.3% 10% $19,094 6% 0.1% 29% 2.0% 13% $53,555 16% 0.1% 28% 3.6% 12% $36,724 8% 0.4% 26% 2.8% 17% $73,816 20% 0.3% 17% 5.6% 20% $59,699 23% 0.9% 18% 4.5% 24% $97,403 25% 0.7% 18% 8.7% 23% $85,170 25% 2.1% 18% 7.5% 31% $131,539 30% 2.9% 11% 15.8% 35% $130,908 38% 7.2% 9% 17.6% 100% $76, % 4.1% 100% 35.0% 100% $66, % 10.7% 100% Trips N P-value <.0001 < <.0001 <.0001 <.0001 In 2013, trips above citywide mean % bachelor, mean income and % Medicaid were 85%, 95% and 8% In 2017, trips above citywide mean % bachelor, mean income and % Medicaid were 86%, 93% and 9% Results

23 Quintile 1 Quintile 2 Quintile 3 Quintile 4 Quintile 5 Bike share participation - other physical activity opportunities Pearson correlation Commute Trips Walk Trips Bicycle Trips Commute Trips Walk Trips Bicycle Trips % 6.4% 5% 0.1% 22% % 4.8% 6% 0.0% 18% % 17.5% 23% 1.2% 26% % 8.5% 9% 0.9% 19% % 24.7% 27% 2.4% 18% % 14.1% 15% 1.9% 22% % 32.0% 22% 3.8% 19% % 24.5% 37% 3.2% 21% % 46.0% 23% 6.4% 15% % 40.7% 33% 6.3% 20% 100% 100% 100% 100% 100% 100% Trips N P-value <.0001 < <.0001 < In 2013, trips citywide mean commute minutes, % walk, % bicycle were 1%, 97% and 67% In 2017, trips above citywide mean commute minutes, % walk, % bicycle were 2%, 87% and 68% Results

24 Bike share participation - physical activity engagement No LTPA Trips No LTPA Trips Quintile % 29% 12.3% 36% Quintile % 26% 14.2% 29% Quintile % 20% 17.2% 17% Quintile % 15% 24.1% 11% Quintile % 9% 35.9 % 7% In 2013, 5.6% of trips were in census tracts with no LTPA above the 28.8% citywide mean. In 2017, this increased to 7% of trips. Pearson correlation 18.6% 100% 20.7% 100% Trips N P-value <.0001 <.0001 In 2013, 3.9% and in 2017, 6.1% of trips took place in a census tract with a % black above the citywide mean. Results

25 Discussion A study strength is the two levels of bike share distribution analyzed (access and participation, given access) Cross-sectional Limited by measures available at the census tract level Spatial-analysis measures of ecological environments have been proposed with more purposeful destinations or boundaries than census tracts Research on bike share mode shifts by SES is needed Discussion

26 Conclusion We found that Citi Bike s distribution was associated with disparities in access and participation by SES. We further found disparities in bike share distribution by other physical activity opportunities and physical activity engagement. It may be that these disparities in access and participation limit the public health impact of bike shares. Public health policies may address SES disparities in bike shares. Discussion

27 Thank you! Any questions? Lori Suzanne suzanne

28 Select References Andersen, L.B., Schnohr, P., Schroll, M., Hein, H.O., All-cause mortality associated with physical activity during leisure time, work, sports and cycling to work. Archives of Internal Medicine 160 (11), Baker PR, Francis DP, Soares, J, Weightman AL, Foster C. Community wide interventions for increasing physical activity. Cochrane Database Syst rev 2015 Jan 5:1:CD Bauman, Adrian. Crane, Melanie, Drayton, Bradley Alan. Titze, Sylvia. The unrealized potential of bike share schemes to influence population physical activity levels A narrative review. Preventative Medicine. February 20, DOI: /j.ypmed Carlos A Celis-Morales, Donald M Lyall, Paul Welsh, Jana Anderson, Lewis Steell, Yibing Guo, Reno Maldonado, Daniel F Mackay, Jill P Pell, Naveed Sattar, Jason M R Gill. Association between active commuting and incident cardiovascular disease, cancer, and mortality: prospective cohort study. BMJ 2017;357:j1456 Goodman, Anna. Green, Judith. Woodcock, James. The role of bicycle sharing systems in normalizing the image of cycling: An observational study of London cyclists. Journal of Transport & Health McNeil, Nathan. Dill, Jennifer. MacArthur, John. Broach, Joseph. Howland, Steven. Breaking Barriers to Bike Share: Insights from Residents of Traditionally Underserved Neighborhoods. Transportation Research and Education Center (TREC) Portland State University. Prepared for: National Institute for Transportation and Communities. June NITC-RR-884b Reeve, Belinda LLB, PhD, Marice Ashe, JD, MPH, Ruben Farias, MS, and Lawrence Gostin, LLD, JD. State and Municipal Innovations in Obesity Policy: Why Localities Remain a Necessary Laboratory for Innovation. J Public Health Policy May;36(2): doi: /jphp Rose, G. Department of Epidemiology, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK. Sick individuals and sick populations. International Journal of Epidemiology 1985;14: Ursaki, Julia and Aultman-Hall, Lisa. Quantifying the Equity of Bikeshare access in US Cities. Submitted August 1, 2015 for review to the Transportation Research Board Phelan JC, Link BG, Diez-Roux A, Kawachi I, Levin B "Fundamental causes" of social inequalities in mortality: a test of the theory. Journal of Health & Social Behavior 45(3): Pucher, J., Buehler, R., Bassett, D. R., & Dannenberg, A. L. (2010). Walking and Cycling to Health: A Comparative Analysis of City, State, and International Data. American Journal of Public Health, 100(10), Saelens BE, Vernez Moudon A, Kang B, Hurvitz PM, Zhou C. Relation between higher physical activity and public transit use. Am J Public Health May;104(5): doi: /AJPH WHO Regional Office for Europe. Health economic assessment tools (HEAT) for walking and for cycle. Methods and user guide, 2014 update.

Webinar: Breaking Barriers to Bike Share: Insights on Equity

Portland State University PDXScholar TREC Webinar Series Transportation Research and Education Center (TREC) 8-22-2017 Webinar: Breaking Barriers to Bike Share: Insights on Equity Nathan McNeil Portland