Introduction
Physical inactivity is a major cause of morbidity and mortality,1 and the creation of opportunities for safe, active mobility has been identified as one central feature of a “healthy city.”2 Promoting a shift away from motorised vehicle travel towards walking and cycling would also be expected to yield additional health, economic, and environmental benefits, including reducing traffic congestion, noise, and the emission of greenhouse gases.3 4 5 One way in which cities can seek to realise these benefits is by implementing bicycle sharing systems to facilitate short term bicycle rental in urban areas. Typically, users of these schemes can borrow a bicycle from any one of several self service stations and drop it off at any other station, making cycling into a form of public transport. Such schemes are increasingly popular around the world, having grown from five schemes in Europe in 2000 to 636 schemes (with an estimated 600 000 bicycles) in 49 countries in 2013.6