This Bike Lane Can Save Your Life (Peter Coy, BloombergBusinessweek)

Adding bike lanes makes a city healthier—even for people who never climb on a bicycle.

Bicycle lanes have been a contentious issue in many U.S. cities, pitting motorists who say there’s no room for more bikes against two-wheel enthusiasts preaching the health benefits of leaving the car at home. But if you lay down enough bike lanes, something magical begins to happen: Non-riders begin to benefit from cleaner air when the network of bike lanes gets complete enough that people start riding bikes to work instead of driving.

Less-comprehensive networks don’t reduce air pollution because people use the lanes only for pleasure riding, which doesn’t displace driving to work, says Babak Mohit, a post-doctoral researcher at Columbia University’s Mailman School of Public Health and lead author of a study published online by the journal Injury Prevention. Additionally, bike lanes make existing riders safer and attract new riders, who get cardiovascular benefits from exercise, according to Mohit and his co-authors, Jing Gu and Peter Alexander Muennig.  

Cities are embracing the idea. According to an article last year by consulting firm McKinsey & Co., “London is building 12 ‘cycle superhighways’—extra-wide lanes dedicated to bicycles.” McKinsey also cites New York, hilly San Francisco, Sao Paulo, Delhi, and even Moscow as cities that are expanding bike-lane networks.

There’s math to show how cost-effective the strategy could be for public health. When New York spent about $8 million in 2015 on bike lane expansion, the cost per additional “quality-adjusted life year,” or QALY, was about $1,300, according to the Mailman paper.

A QALY, pronounced “qually,” is a standard measure of cost-benefit analysis. It takes into account the number of people who benefit from an intervention, how many years of extra life they can expect to get, and how healthy they will be during the extra years.

As it turns out, when you apply this to bike lanes, it makes them more economical per added QALY than, say, kidney dialysis, which costs over $100,000 per QALY—although not quite as cost-effective as standard vaccines, which cost in the low hundreds of dollars per QALY, Mohit said.

That’s not an argument for yanking people off dialysis machines and using the money to build bike lanes, but it does support the idea that “investments in bike lanes are more cost-effective than the majority of preventive approaches used today,” the paper states.

"While we use NYC as an example, our intent is to provide a much more generalisable model, such that localities can estimate the return on their investment in bike paths," the authors write.