The Transport Health Assessment Tool for Melbourne (THAT-Melbourne) was developed as part of a larger research partnership project with the Victorian Department of Transport (DoT). The project was led by Dr Lucy Gunn, Dr Belen Zapata-Diomedi, Dr Alan Both, Dr Annette Kroen, Dr Chris De Gruyter and A/Prof Melanie Davern at RMIT University along with Hugh Batrouney, Dr Morteza Chalak, Anh Nguyen, and Rick Williams from the Victorian Department of Transport. The project was funded by an RMIT University Enabling Capability Platform Opportunity Fund on Research Translation and Impact and with in-kind support from the Victorian Department of Transport.
The Transport Health Assessment Tool for Melbourne (THAT-Melbourne) was developed as a quantitative health impact assessment (HIA) model within the partnership project with the Victorian Department of Transport (DoT). THAT-Melbourne was designed as an accessible tool available to the public via the Australian Urban Observatory supporting translation of this research knowledge. It was designed for a range of audiences to increase understanding about the implications of transport decision-making on health.
Active transport, such as walking and cycling, provides an important opportunity to increase daily physical activity, particularly when more than half of Australians did not meet the requirements for physical activity as summarised in the 2017-18 National Health Survey. Health benefits gained through physical activity also continue to accumulate across the lifespan and have major long-term social and economic consequences. Physical activity has many health benefits and reduces the chance of chronic diseases such as cardiovascular disease, diabetes, cancer, dementia, and also death from all causes.
What is the Transport Health Assessment Tool for Melbourne?
The tool has been designed to measure health impacts associated with increased physical activity due to replacing short car trips under 10km by walking and cycling in Melbourne. These health impacts are assessed through 20 different scenarios where short car trips are replaced with walking, cycling or a combination of both walking and cycling.
Why was it developed?
The Transport Health Assessment Tool for Melbourne is a freely accessible tool that measures and quantifies health benefits derived from replacing short car trips with walking and cycling. The tool provides important research evidence to support and advocate for active transport and to make the connection between the influence of transport policies on health.
How was it developed?
Active transport scenarios are used to measure and model the impact on disease risk because of changes in physical activity from increased walking and cycling. The diseases included in the model are: ischaemic heart disease; stroke; diabetes mellitus type 2; colon cancer; lung cancer; and breast and uterine cancers in females. The model follows the Melbourne population with baseline year of 2017 until people they die or reach the age of 100. Health benefits from physical activity accumulate over a lifespan. So, becoming active earlier in life has greater health benefits across the lifespan and is reflected in the incidence and mortality of disease.
Age and gender are important influences on disease risk, transport behaviour and physical activity patterns. The model accommodates differences for age and sex for a base case scenario (no changes to walking/cycling) and for each of possible scenarios beginning in 2017.
The model begins in 2017 because of data availability from the Victorian Integrated Survey of Travel and Activity (VISTA) 2017-18 and the National Health Survey (2017-18). Results from the model include the number of cases of chronic disease and deaths prevented, Health Adjusted Life Years (HALYS) and Life Years. HALYs represent years of life, adjusted according to decreased quality of life caused by disability, disease or injury.
Health impacts can be calculated from 20 different walking and cycling scenarios applied to replace car trips. These include trips replaced by walking (2 scenarios of different distances), cycling (3 scenarios of distance) and combined walking and cycling together (5 scenarios of different distances).
Trips are further categorised according to trip purpose – either commuting trips or all trips. Commuting trips are those related to work or education. The definition of all trips includes transport related trips to work, education, leisure, shopping, picking-up or dropping-off someone or something, or accompanying someone. Finally, the scenario combinations of walking/cycling and trip purpose were applied to age groups and gender.
In this tool we capture increases in physical activity associated with active transport scenarios and simulate potential health outcomes that come from this for the Melbourne population in 2017. Outcomes include the reduction in incidence, mortality and health benefits in the form of Health-adjusted life years (HALYs) and Life Years.
The model has three sections:
- 1. Scenarios;
- 2. Potential Impact Fractions (PIF) representing a measure of the proportional change in disease risk due to an increase in physical activity; and
- 3. Proportional multi-state life table (PMSLT).
We developed a hybrid model, where the scenarios and PIF calculations are at the individual level (micro-simulation) and the PMSLT calculations are at the macro level aggregated by age and sex groups (macro-simulation).
The figure below provides a schematic of the modelling process that underlies the Transport Health Assessment Tool for Melbourne (THAT-Melbourne).
More details of the methods can be found in the Technical Report.
The team gratefully acknowledges the funding from the RMIT University’s Enabling Capability Platform Opportunity Fund for Research and Impact and the support of our project partners from the State Government of Victoria at the Department of Transport. We further acknowledge the RMIT University Centre of Urban Research, the Urban Futures Enabling Capability Platform and the Australian Prevention Partnership Centre.
We acknowledge the technical contributions from the Public Health Modelling Team at the MRC Epidemiology Unit at the University of Cambridge. The contributions of Dr Ali Abbas were funded by the European Research Council under the Horizon 2020 research and innovation programme (grant agreement No 817754) under the GLASST: Global and local health impact assessment of transport project.
Dr Belen Zapata-Diomedi was funded by a RMIT University Vice-Chancellor’s Postdoctoral Fellowship with some components of the code development completed during her placement at the MRC Epidemiology Unit, University of Cambridge under the supervision of Dr James Woodcock. THAT-Melbourne, builds on the original model1 further developed by Zapata-Diomedi et al (2019)2.
1 Cobiac, L.J., Vos, T. and Barendregt, J.J., 2009. Cost-effectiveness of interventions to promote physical activity: a modelling study. PLoS Med, 6(7), p.e1000110.
2 Zapata-Diomedi, B., Boulangé, C., Giles-Corti, B., Phelan, K., Washington, S., Veerman, J.L. and Gunn, L.D., 2019. Physical activity-related health and economic benefits of building walkable neighbourhoods: a modelled comparison between brownfield and greenfield developments. International Journal of Behavioral Nutrition and Physical Activity, 16(1), pp.1-12.