The recent proliferation of bike share schemes (BSS, also known as public bicycle use programs) in many cities has focused attention on their potential for reducing motorised traffic congestion, improving air quality and reducing car use. Since 2005, hundreds of bike share schemes have been implemented in many cities, with bike share usage patterns monitored in many of them. This paper assesses the development of BSS and provides a rationale for their potential health benefits. The key research question, as yet unanswered, is whether BSS themselves can contribute to improving population health, particularly through increasing population cycling, which would increase population levels of health-enhancing physical activity. This paper presents a framework for evaluating the contribution of BSS to population physical activity, and uses examples of new data analyses to indicate the challenges in answering this question. These illustrative analyses examine cycling in Australia, and [i] compares rates of cycling to work in BSS cities compared to the rest of Australia over time, and [ii] modelling trends in bike counts in Central Melbourne before and after introduction of the BSS in 2010, and compared to adjacent regions in nearby suburbs unexposed to a BSS. These indicative examples point to difficulties in attributing causal increases in cycling for transport to the introduction of a BSS alone. There is an evidence gap, and a need to identify opportunities to improve the health-related components of BSS evaluations, to answer the question whether they have any impact on population physical activity levels.
