Today the Census Bureau released its annual estimate of how Americans get to work, according to the 2015 American Community Survey (ACS). The Census Bureau began releasing annual estimates in 2005 and, unfortunately, 2015 is the first year since 2010 that the fastest growing mode of getting to work — biking — has shown a slight decline. According to the ACS, there was a 3.8% decrease in people who used a bicycle as their primary mode of transportation to work in 2015.

Find data on bike commuting in large cities here

Before pundits start declaring that millennials are jumping off their bikes and climbing into mini SUV's there are some things to keep in mind. In particular, two outside factors could help explain this drop: 1) gas prices remain low and stable and 2) vehicle miles traveled (VMT) has increased sharply. VMT exploded in 2015, with the western US reporting a 7% increase from December 2014 to December 2015. With lower gas prices and a greater availability of car sharing services, such as Uber and Lyft, there may be people who have chosen to substitute car trips to work for bike trips. This increase in driving has also been accompanied by an increase in traffic fatalities, with bicyclists and pedestrian fatalities seeing the largest increases.

There is still good news. 43 of the 70 largest cities have not experienced 2015's hiccup and have continued to see more people biking to work. There are now more cities with a 4% or greater mode share (the percentage of working using bikes to get to work), including the Uber's hometown of San Francisco. Portland continues to have 7% of its workers using bikes to get to work and launched a bike share system this year that should enable more people to bike work. Minneapolis continued its trend of more people biking to work, with 5% of people biking to work. Washington DC and Seattle also come in at 4% or above. Philadelphia, which had a hiccup in 2014, now exceeds the 2% mode share threshold, making it the only city with more than 1 million residents that exceeds 2% mode share. Although that might not be for long as Chicago's steady growth remains uninterrupted.

It is important to remember that the development of protected bike lanes, bike share, and other efforts that promote bicycling to work and for utilitarian purposes are still in their early development stages. While there are over 4 million miles of roads in the US we currently have less than 200 miles of protected bike lanes. The same can be said for bike parking and other amenities that make bicycling easy and convenient.

The Census Bureau data provides a valuable barometer of bicycling in America, but to really understand how bicycling is faring the US we need to be able to collect and aggregate more data. The League applauds FHWA and the many communities that are investing in bicycle count technology to gain a better understanding of how many people bike. We need our transportation agencies to collect the same data on bicyclists and pedestrians that they do for motor vehicles and transit. That will enable Americans to make sound investments in bicycling and walking to make getting from point A to point B safer and more enjoyable.