The Value of Bike Sharing: Looking Beyond Carbon Emissions

While the sharing economy fan base continues to expand, questions rise  about the true economic and social impacts of sharing.

Interestingly, one part that is still missing from these discussions (well, not entirely) is the environmental impacts of the sharing economy. The general notion is that the sharing economy has a positive environmental impact as it promotes a greater use of underutilized assets. But is this true?

This answer no doubt is complicated. There are even doubts about the environmental impacts of first appears to be one of the greener parts of the sharing economy – bike sharing.

As Bobby Magill reported recently on Climate Central, while we know for sure that nobody has ever died on a bike-share bike, we can’t really be sure what impact bike sharing has on climate change.

It’s not that we don’t know that riding a bike is better for the climate or that we can’t quantify it – “Each mile someone rides on a bike-share bike instead of driving a car means about one pound of carbon dioxide is kept out of the atmosphere,” according to Dr. Susan Shaheen. The problem is that we don’t know for sure how many people ride a bike as an alternative to driving a car and that the data varies greatly from city to city. However, the estimate is that on average less than 20 percent of the riders switch from cars, according to Prof. Ralph Buehler.

Now, is it really that important to know how many riders use the bike instead of a car? Theoretically yes, because the environmental impact is more significant if you use a bike-sharing service as an alternative to driving your car compared to using it instead of using public transit. However, practically, it doesn’t seem to matter that much.

Why? Let’s see the numbers.

So far, more than 23 million bike trips were made in the U.S. with bike-sharing services. To calculate how many miles these trips covered we’ll use information from B-Cycle, the company that designs the bike-sharing systems used in most cities across the U.S. According to Climate Central, the company claims that 2.1 million bike trips covering 4.5 million miles have been made on all of its systems since 2010 -- or, in other words, 2.14 miles per trip. Looking at New York Citibike’s latest data from April (1.07 mile per ride) and May 2014 (1.8 miles per ride), the B-Cycle figure seems pretty conservative.

If you multiply 23 million rides at 2.14 miles per ride, you get 49.22 million miles. Using Dr. Saheen’s estimate of one pound of carbon dioxide that is kept out of the atmosphere for every mile someone rides a bike instead of using their car, we could say that -- if all 49.22 million bike-miles were an alternative to car-miles -- then bike-sharing systems have saved 22,326 metric tons of C02 so far.

Is this impact significant? Not really. Using data from the EPA and the Union of Concerned Scientists, I’ve calculated that even if all of the 23 million rides were an alternative to car-miles it would offset only 10 minutes of car- and light truck-driving in the U.S. (2012 data).

So, does this mean that bike-sharing programs are not as green as we might assume? Well, not so fast.

“The ultimate goal of public bike sharing is to expand and integrate cycling into transportation systems, so that it can more readily become a daily transportation mode (for commuting, personal trips, and recreation),” Dr. Shaheen an three other researchers write in a study published in 2012 (Public Bikesharing in North America: Early Operator and User Understanding).

I believe the authors are right. Rather than looking at bike-sharing systems through the narrow lens of their direct impact on climate change, health, traffic congestion or even environmental awareness, we should use a much broader framework when evaluating their impact and value: city residents’ well being.

What I mean is that the main 'green' challenge bike-sharing programs address is not necessarily climate change but mobility in cities. “Of every one hundred American commuters, five take public transit, three walk and only one rides a bicycle to work or school,” Charles Montgomery writes in his book “Happy City.”

Montgomery notes that it’s no coincidence that even in dense, connected American communities very few people use bikes, which “is rated the most fun, efficient and joyful” travel mode. The reason, he explains, lies in the intersection between psychology and design. In other words, our travel choices are greatly influenced by the way cities are designed and the perception we have of different travel modes. In both cases, bikes seem to be in a disadvantaged position compared to all other modes of transportation; American cities are not designed with bikes in mind, and many people don’t think of biking as a joyful, efficient, convenient and safe choice.

This is where bike-sharing programs can make a difference. We should look at them as an intervention aimed to change the dynamics of mobility in cities, making bike riding more accessible, safe and desirable, and thus increasing residents’ well being.

Looking at these criteria, I believe so far bike-sharing programs perform pretty well. They provide a relatively affordable access to bike riding without the need to own a bike (a product service system); they increase riders’ safety as a greater presence of bikes forces motorists to drive more carefully (and thus “the cities with the largest share of cyclists have the fewest cycling fatalities”); and finally, they also seem to help improve the image of cycling.

So, when it comes to how green bike-sharing programs are, the focus should be their well-being impact, not their climate impact. The framework for this discussion should be urban mobility, not carbon emissions, and it’s true not just in terms of having the right discussion, but also in terms of communicating this issue. After all, what would get people more excited about bikes – knowing that they will save X metric tons of carbon emissions or that their rush-hour might look like this?

Image credit: Steven Rhodes, Flickr Creative Commons

Raz Godelnik is an Assistant Professor of Strategic Design and Management at Parsons The New School of Design. He lives in Brooklyn and likes to ride his own bike. You can follow Raz on Twitter.