Gymnastik- och idrottshögskolan, GIH

Objectives: To estimate the overall health impact of transferring commuting trips from car to bicycle..

Design and setting: In this study registry information on location of home and work for residents in the County of Stockholm was used to obtain the shortest travel route on a network of bicycle paths and roads. Current modes of travel to work were based on travel survey data. The relation between duration of cycling and distance cycled was established as a basis for selecting the number of individuals that normally would drive a car to their work place, but have a distance to work that they could bicycle within 30 minutes. The change in traffic flows was estimated by a transport model (LuTrans) and effects on road traffic injuries and fatalities were estimated by using national hospital injury data. Effects on air pollution concentrations were modelled using dispersion models.

Results: Within the scenario, 111 000 commuters would shift from car to bicycle. This corresponds to 32% of the existing car commuters. On average the increased physical activity reduced the one-year mortality risk by 12% among the additional bicyclists corresponding to 16 fewer premature deaths per year. Including the number of years lost due to morbidity, the total number of disability adjusted life years (DALYs) gained was 696. The amount of DALYs per year gained in the general population due to reduced air pollution concentrations at home addresses was 471. The number of DALYs lost by traffic injuries was 176. Including also air pollution effects among bicyclists, the scenario was calculated to each year give a net benefit of 939 DALYs.

Conclusion: The health impact assessment of transferring commuting by car to bicycle estimated large health benefits even then considering injuries and air pollution exposure among bicyclists.