The mortality impact of bicycle paths and lanes related to physical activity, air pollution exposure and road safety

Objective: Guidelines for bicycle infrastructure design tend to consider safety issues but not wider health issues. This paper explores the overall health impact of bicycle infrastructure provision, including not just road safety impacts, but also the population health impacts stemming from physical activity as well as cyclists' exposure to air pollution. Data and methods: We have summarised key publications on how bicycle paths and lanes affect cyclists' exposure to physical activity, air pollution, and road safety. The health impact is modelled using all-cause mortality as a metric for a scenario with new bicycle lanes and paths in a hypothetical city. Results: The outcomes of the study suggest that, based on currently available research, a reduction of all-cause mortality is to be expected from building bicycle lanes and paths along busy roads with mixed traffic. Increased physical activity through more time spent cycling is the major contribution, but is also the most uncertain aspect. Effects related to air pollution and cycling safety are likely to reduce mortality but are small. The overall benefits are large enough to achieve a high benefit-cost ratio for bicycle infrastructure. Conclusions: The introduction of bicycle paths and lanes is likely to be associated with health benefits, primarily due to increased physical activity. More research is needed to estimate the absolute size of the health benefits. In particular, evaluations of the effects of bicycle infrastructure on time spent cycling are limited or of insufficient quality to infer causality. We recommend before-after studies measuring the effects of different interventions and in areas representing a wide range of base levels of cycling participation