摘要：Objectives. We examined associations between residential exposure to BIXI (BIcycle-taXI)—a public bicycle share program implemented in Montreal, Quebec, in 2009, which increases accessibility to cycling by making available 5050 bicycles at 405 bicycle docking stations—and likelihood of cycling (BIXI and non-BIXI) in Montreal over the first 2 years of implementation. Methods. Three population-based samples of adults participated in telephone surveys. Data collection occurred at the launch of the program (spring 2009), and at the end of the first (fall 2009) and second (fall 2010) seasons of implementation. Difference in differences models assessed whether greater cycling was observed for those exposed to BIXI compared with those not exposed at each time point. Results. We observed a greater likelihood of cycling for those exposed to the public bicycle share program after the second season of implementation (odds ratio = 2.86; 95% confidence interval = 1.85, 4.42) after we controlled for weather, built environment, and individual variables. Conclusions. The implementation of a public bicycle share program can lead to greater likelihood of cycling among persons living in areas where bicycles are made available. The relationship between transportation and health is of growing interest in public health. 1,2 Studies show associations between high levels of cycling for transportation or utilitarian cycling and reduced traffic congestion, 3 noise and air pollution, 4 and obesity as well as increases in physical activity. 5–7 Cycling contributes to overall physical activity, which is associated with a number of health benefits including reduced body mass index (BMI; defined as weight in kilograms divided by the square of height in meters), reduced waist circumference, and improved blood lipid profiles (i.e., total cholesterol, low-density lipoprotein cholesterol, and triglycerides). 8–12 As well, modeling studies suggest that the health benefits of physical activity resulting from increased cycling would outweigh the risks of collisions and exposure to air pollution. 13,14 In North America, the potential of cycling as a means to augment population levels of physical activity is also evidenced, at least in part, by its low prevalence even in densely built urban areas. In Canada, the proportion of individuals who cycled to work was 0.6% in 2006 and in the United States the share of bicycle commuters was 0.55% in 2008. 15,16 The current low prevalence and the positive health benefits of greater cycling explain why initiatives to promote cycling, particularly cycling for transportation, are now a major public health aim. To date, only a small number of built environment interventions to promote cycling have been evaluated. 17–23 These intervention studies have shown small but statistically significant associations between intervention implementation and self-reported cycling. 17–19 However, a variety of potentially effective built environment interventions have been implemented but not evaluated. Public bicycle share programs (PBSPs), widely implemented in Western European cities, increase population access to bicycles by making bicycles available at docking stations throughout an area within a city for a fee. 22,24 For example, Montreal’s BIXI (BIcycle-taXI) program, North America’s largest in 2011, launched in May 2009, makes available 5050 bicycles at 405 docking stations within an area of approximately 46.5 square kilometers, encompassing about 380 000 inhabitants. Bicycles are available for a check-out fee of $5 for 24 hours, $48 for a month, or $78 for the season. After payment of the check-out fee, the first 30 minutes of usage is free. Users extending their usage beyond 30 minutes pay a usage fee of approximately $1.50 per 30 minutes. Two recent studies have provided evidence that PBSPs have the potential to contribute to population levels of cycling and may, as a result, increase population levels of physical activity. 24 Approximately 8% of the population of Montreal had used BIXI at least once in the first year of implementation. 25 Cycling behavior before the implementation of the program and having a university education were positively correlated with likelihood of using the program at least once. A health impact assessment of the Bicing program in Barcelona showed that, compared with car users, the annual change in mortality for the 181 982 Bicing users was an additional 0.03 deaths from road traffic incidents, 0.13 deaths from air pollution, and 12.46 deaths avoided as a result of physical activity. The estimated annual number of deaths avoided as a result of Bicing was 12.28. 14 However, despite initial evidence showing adoption and positive health benefits, to date, there is limited evidence that PBSPs actually increase overall cycling rates in cities where they are deployed. 22,24 The primary objective of the present study was to examine whether exposure to Montreal’s BIXI program (a built environment intervention) would be associated with increases in total cycling, including cycling on BIXI and personal bicycles. We hypothesized that the implementation of BIXI would be associated with an increased likelihood of cycling for those exposed. Ancillary analyses examined whether increases in cycling are attributable to increases in utilitarian or recreational cycling. We hypothesized that utilitarian cycling would contribute more to the hypothesized increases in total cycling because BIXI is implemented in an urban area with high densities of destinations and targets utilitarian cycling (i.e., 30-minute free period). In sensitivity analyses, we examined whether associations for total cycling remained statistically significant for durations that could contribute to meeting public health recommendations for physical activity.
