AIR POLLUTION AND TRAVEL TO SCHOOL – PART I: A THEORETICAL BI-MODAL SCHOOL TRIP MODEL

Promoting modal shift from being driven to school to walking has received a high level of attention from transport authorities around the world and the task has been proved challenging. Most studies have looked at the potential benefits of the increase in physical exercise but no studies exist looking at the benefits of reduction in pollutant dose induced by the modal shift specifically from being driven to walking. We propose a theoretical bi-modal school trip model to analyse the interplay of mode choice, i.e. being driven or walking to school, the environment (air quality) and the impact on the health of children (dose). The air quality assessment is dependent on the traffic speed and associated traffic density during the journey, which is a result of the mode choices of the pupils as well as the location of the school. We considered two cases of school location: at a cul-de-sac and on a busy road. We show how the pollutant dose will be dependent on both the level of background traffic and the school-specific traffic at different locations. With this theoretical model, it is possible to assess the extent to which we can achieve benefits from walking to school and what conditions would be needed for there to be any benefit from the point of view of the dose experienced by the school’s children in the course of their commute. Our model results provide insights into what policies under what conditions benefits from walking to school could be achieved.