You might be surprised.
The cost of a bike lane averages $130,000 per mile.
The cost of an urban road averages $4,000,000 per mile, per lane.
Not to mention better bike infrastructure reduces car traffic: more bikes means fewer cars, the bike infrastructure is not simply additive.
Plus secondary economic benefits: civil density, reduced parking costs, reduced healthcare costs, reduced environmental costs, reduced oil & gas imports, ...
Did you know a parked car takes up 10 times as much space as a parked bicycle?
Did you know there are approximately 10 parking spaces per car in America?
Take away the driving subsidies and everyone would be riding bikes demanding better infrastructure.