Others have said that every 20 minute bike trip equals AUD$14.30 to the Australian economy, that cycling is worth DKK1.22 per km to Danish economy, and that accounting for fuel and health savings and factoring in the value of saved lives, Portland OR gains $5 for every $1 it spends on bike infrastructure. Facts like these are usually taken as evidence that slowing the pace of city life is in some counterintuitive way, good in terms of economics. I think that’s a misreading.
Quite aside from the health and fuel savings, cycling increases mobility and access in a city. Cities with good cycling amenity draw more economic activity from each person living there, every day. How much more could each of us achieve every day in a city actually designed around cycling? I don’t want to waste my life nibbling at car space. I want to inspire someone, somewhere, to build a new city from scratch, without any cars. I want to see a city with the population of Sydney, but covering a land mass one-twentieth the size, and I want there to be no cars in sight. I don’t care if this happens in the first world, or third, or if it has to happen on urban wastelands. I just want it to be shown to be feasible, and advantageous, to give the entire ground plane of a city to cycling, and let people make bee-lines to their destinations with no interruption from motorised vehicles.