Photo by Mikael Colville-Andersen.

Copenhagen, the bicycle-friendliest place on the planet, publishes a biannual Bicycle Account, and buried in its pages is a rather astonishing fact, reports Andy Clarke, president of the league of American Bicyclists:

“When all these factors are added together the net social gain is DKK 1.22 per cycled kilometer. For purposes of comparison there is a net social loss of DKK 0.69 per kilometer driven by car.” 1.22 Danish crowns is about 25 cents and a kilometer is 6/10 of a mile, so we are talking about a net economic gain to society of 42 cents for every bicycle mile traveled. That’s a good number to have in your back pocket.

And what are all the “social gains” that bicycling grants the city of Copenhagen?

A number of factors are included in the equation such as transport costs, security, comfort, branding/tourism, transport times and health.

Considering that both sitting and car exhaust kill you, it’s a safe bet a lot of the net benefit to society is simply that cycling makes you less of a drag on health insurance and the safety net.

Since the total health benefit of Copenhagen residents’ healthy cycling habits is DKK 5.51 per km, the annual benefit is worth the equivalent of approx. DKK 2.0 billion.

Which means that Copenhagen, a city of 1.2 million people, saves $357 million a year on health costs because something like 80 percent of its population commutes by bicycle, even in winter. That’s $300 per person per year. Clearly, the reason the new Danish minister of the interior said she’d “rather invest in cycle tracks than freeways,” is that only one of those has a positive return.