Healthy transport
The environmental benefits of public transport are obvious. When compared to driving by car there is reduced carbon emissions, improved local air quality, less noise, the list goes on. But the health benefits are rarely factored in to societies total impact on the environment.
If we live healthier lifestyles our cost and impact on society and the planet is reduced. When we live more healthy lifestyles there is less heart disease, less obesity, less mental health issues, the list goes on. There is an environmental and carbon impact of healthcare in the same way that there is an environmental and carbon impact of driving a car. Reducing the demand on healthcare reduces the impact of healthcare.
So when we consider and analyse public transport versus private car use in terms of environmental benefit we should also include the environmental benefit of the health improvements associated with public transport.
Maybe we should think about renaming Public Transport to Healthy Transport to change the perception or stigma to get more cars off the road. “How do you travel to work?” “Oh, I catch Healthy Transport.” Yeah much better.
So, what is the carbon footprint for a broken leg from a traffic accident compared to the carbon reduction of using public transport? What is the cost difference? Maybe if the cost of healthcare was factored into the cost of our Healthy Transport infrastrucutre it might pay itself back much sooner? Maybe the cost reduction of healthcare could pay for the Healthy Transport system!
SIMON WILD 
interesting point. not sure how one might calculate such a figure. but i’m sure someone could.