Does bike sharing improve public health? A case study in New York City

Bike sharing contributes to public health by providing physical exercise opportunities. Meanwhile, the shift of vehicular travel demand to bike sharing may cut vehicular emissions and severe crashes. However, according to each city's different composition of travel modes, the net health benefits are not clear and worth studying case by case. In this paper, we focus on the Citi Bike bike-sharing program in New York City. We modify the Integrated Transport Health Impact Model and assess the net health effects by comparing a baseline scenario (with Citi Bike) against a hypothetical scenario (without Citi Bike). For each scenario, we investigate the overall health effects of the Citi Bike program in the unit of Disability Adjusted Life Years (DALYs) in three categories: physical activity, fine inhalable particles (i.e., PM 2.5) exposure, and road traffic injuries. The results indicate that the implementation of Citi Bike plays a positive role in improving public health. It is worth noting that the emission reduction due to the shift from vehicular transport to Citi Bike contributes the most health benefit to the public. Hence we further propose a sensitivity analysis of the Citi Bike market share illustrating the potential benefits of promoting Citi Bike among non-users.