The Societal Costs and Benefits of Commuter Bicycling: Simulating the Effects of Specific Policies Using System Dynamics Modeling

Alexandra Macmillan , Jennie Connor, Karen Witten, Robin Kearns, David Rees, and Alistair Woodward

School of Population Health, University of Auckland

2014

Environmental Health Perspective online. Advance publication 4 February 2014

Alexndra McMillan

School of Population Health,

University of Auckland

Background: Shifting to active modes of transport in the trip to work can achieve substantial co-benefits for health, social equity and climate change mitigation. Previous integrated modeling of transport scenarios has assumed active transport mode share and been unable to incorporate acknowledged system feedbacks.

Objectives: To compare the effects of policies to increase bicycle commuting in a car-dominated city and to explore the role of participatory modeling to support transport planning in the face of complexity.

Methods: We used system dynamics modeling (SDM) to compare realistic policies, incorporating feedback effects, non-linear relationships, and time delays between variables. We developed an SD model of commuter bicycling through interviews and workshops with policy, community, and academic stakeholders. We incorporated best available evidence to simulate five policy scenarios over the next 40 years in Auckland, New Zealand. Injury, physical activity, fuel costs, air pollution, and carbon emissions outcomes were simulated.

Results: Using the simulation model we demonstrated the kinds of policies that would likely be needed to change a historical pattern of decline in cycling into a pattern of growth that would meet policy goals. Our model projections suggest that transforming urban roads over the next 40 years, using best practice physical separation on main roads and bicycle-friendly speed reduction on local streets, would yield benefits 10-25 times greater than costs.

Conclusions: To our knowledge, this is the first integrated simulation model of future specific bicycling policies. Our projections provide practical evidence that may be used by health and transport policy-makers to optimize the benefits of transport bicycling while minimizing negative consequences in a cost effective manner. The modeling process enhanced understanding by a range of stakeholders of cycling as a complex system. Participatory SDM can be a helpful method for integrating health and environmental outcomes in transport and urban planning.

Keywords:

cycle commuting, active transport, co-benefits

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Qualitative

Auckland

Physical activity

Community, Outdoors

Accomodation and facilities, Facilities (outdoor)

Benefits, Delivery, Impacts - economic, Impacts - environmental, Impacts- social, Participation, Planning, Policy

Cycling/biking

1839

February 10, 2014