In the hysteria that predated the launch of New York's bike-sharing system last year, many critics cried that the bikes would make the city's streets less safe. All those cyclists wouldn't be wearing helmets! They'd have no insurance! Accidents would skyrocket, and with them lawsuits against the city. Fatalities would triple!

The system's safety record quickly turned out to be less sensational. But this was as bike advocates expected. Biking -- as with walking -- offers a prime example of the power of crowds. As more people bike and walk, cycling and pedestrian fatalities actually decline. That's because the more people bike and walk, the more drivers become attuned to their presence (either on sidewalks or road shoulders), and the more cities are likely to invest in the kind of infrastructure explicitly meant to protect them (all of which further encourages more cyclists and pedestrians).

This pattern is confirmed in a large biannual benchmarking report released this week by the Alliance for Biking & Walking in partnership with the Centers for Disease Control and Prevention. The report, based on data from census travel surveys, the American Community Survey, and local data tracking cyclists and pedestrians, offers some crucial national perspective outside of cities like New York and Washington.

While biking seems to be dramatically on the rise there (and it certainly is in the headlines), only about 1 percent of all trips taken in America today are made on a bike. In 2005, 0.4 percent of commuters cycled to work. By 2011, that figure had ticked up to just 0.56 percent. Walking to work has also barely increased.

But while alternative modes of transportation still account for a small fraction of how we get around (and this remains true of transit, too), it's clear that the more people who bike and walk, the safer those alternatives become. Consider first this chart of the share of commuters who regularly get to work by biking or walking in the largest cities in the U.S. (Yes, in bike-obsessed Portland, still only about 6 percent of people cycle to work):

This chart compares those commute shares to cycling fatalities:



Alliance for Biking & Walking, fatality rate is per 10,000 commuters

And pedestrian fatalities:



Alliance for Biking & Walking

The cities with the largest share of cyclists have the fewest cycling fatalities. And the same is true of pedestrians. Those graphs don't reveal how much of the safety benefit is attributable to infrastructure (bike lanes, crosswalks) and how much to human attention and social norms. But likely the two go together.