A review of transport-health system dynamics models

Introduction:

The impacts of transport on health have been extensively studied, yet there has been less focus on the complex interactions that exist within the transport-health sphere. We adopt a System Dynamics (SD) approach to addressing the research question “Where are the trade-offs and synergies between different types of health impacts within the transport-health system?“, which is in recognition of the problem that policies designed to influence health outcomes related to one form of transport impact may also influence other health outcomes and transport impacts.

Methods:

To begin, we carry out a literature review of existing SD studies of transport-health, identifying 23 that have been published, of which six explicitly cover multiple transport impacts. We then combine key concepts of these studies to create a generalised causal loop diagram (CLD) that addresses the research question.

Results:

We develop a CLD for exploring the trade-offs within transport-health. In doing so, we find that not all existing studies define health outcomes (eg morbidity or mortality) and few cover both transport and health mechanisms in detail. As well as improving the detail on mobility behaviours, transport impacts and health outcomes, we also identify a need for this approach to consider the influence of new data and technologies on transport-health.

Conclusions:

Although this paper presents a qualitative model, this is the first step towards a quantitative model, and nonetheless, in itself may be used to better understand the system and scenarios, and contribute to more robust transport-health impact assessments for policy making.