In Denmark's most populated and largest city, Copenhagen, bikes account for 50 percent of its residents' trips to school or work. Half. Half of commuting happens on a bike in Copenhagen and that doesn't just improve fitness levels and reduce carbon emissions, it also contributes to the wealth of the city, reported Forbes:
Researchers found that for every kilometer traveled by bike instead of by car, taxpayers saved 7.8 cents (DKK 0.45) in avoided air pollution, accidents, congestion, noise and wear and tear on infrastructure. Cyclists in Copenhagen cover an estimated 1.2 million kilometers each day –- saving the city a little over $34 million each year.
What's more, just 30 minutes of daily biking adds an average of one to two years to the life expectancy of Copenhagen's cyclists.
Additional reasons and source .