Dr Adrian Davis
Top line: To convey maximum benefit to population health, interventions need to consider physically inactive people in particular and encourage active travel amongst this group.
Cycling and walking are transport modes that have potential public health and environmental benefits. Various programmes and interventions have been developed and evaluated that aim to increase active travel levels, including the Model Communities Programme in New Zealand, which increased active trip rates by about 30% relative to control areas.
More recent research shows there was little difference in the proportion of control area respondents who increased their active travel mode share when compared across baseline levels of cycling/walking. Compared to similar people in matched control areas, people who reported moderate to vigorous walking and cycling at baseline had 24 times the odds of increasing active travel mode share over the course of the study compared to people who did not report any cycling and walking at baseline. Only a very small proportion of intervention area respondents who were inactive at baseline went on to increase active travel mode share.
Analysis of behaviour change according to distance from the new walking and cycling infrastructure controlling for age, sex and baseline walking/cycling physical activity found that those closer to new infrastructure were more likely to increase their activity. However, the association was weak.
The authors argue that the results have significant implications for the design of interventions to increase active transport levels. Increasing active travel conveys important population health benefits from increasing physical activity levels among a relatively sedentary population. The greatest marginal gain in health is for people with very low physical activity levels who engage in active travel, with an accompanying increase in physical activity. Smaller – but still important – improvements in health arise from increasing physical activity levels of people who are already moderately physically active. Nevertheless, an intervention that fails to benefit a subgroup of the population that most needs to increase physical activity levels needs to be examined and potentially focused differently.
The risk with interventions such as those reported here is that they may entrench existing inequalities in health outcomes, if interventions are only successful for people who already walk and cycle.
 Keall, M. et al, 2015. Increasing active travel: Results of an quasi-experimental study of an intervention to encourage walking & cycling, Journal of Epidemiology & Community Health, 205466.
 Keall, M. et al, 2018 Are people who already cycle and walk more responsive to an active travel intervention? Journal of Transport & Health.No 172: Active travel interventions need to be attractive to the physically inactive Download pdf