The EU has calculated its subsidy to driving is €500 billion per year.
Also, even at the current low rates of walking and cycling due to unpleasant traffic environments:
“Due to positive health effects, cycling is an external benefit worth €24 billion per year and walking €66 billion per year.”
In NZ, the subsidy to driving per capita will be significantly higher than it is in Europe due to our sprawl and high car dependency.
This information could be useful when you are face-to-face with regressive car dependent people complaining about spending money on cycleways or arguing against the changes to our systems that would boost cycling numbers, such as 30 km/hr speeds. Cycleways give us a return on investment. Roads are what cost too much.