From: Benjamin.Thielen
Sent: Monday, August 18, 2014 3:04 PM
To: FedsOnBikes
Subject: The Societal Costs and Benefits of Commuter Bicycling

Of possible interest.

Regards,

Ben Thielen

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

Alexandra Macmillan,1 Jennie Connor,2 Karen Witten,3 Robin Kearns,4 David Rees,5 and Alistair Woodward1

http://ehp.niehs.nih.gov/wp-content/uploads/122/4/ehp.1307250.pdf

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 has been unable to incorporate

acknowledged system feedbacks.

Objectives: We compared the effects of policies to increase bicycle commuting in a car-dominated

city and explored 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, nonlinear relationships, and time delays between variables. We developed a system

dynamics 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.