Capital Bikeshare had its 10 millionth ride earlier this summer

It took 1 year to get the first million rides in, and less than four for the next 9 million. 

On June 4, 2015, a bike taken out by a founding member from September 2010 traveled from 14th St & D St NW / Reagan Building to 8th St & D St NW to become the 10 millionth trip taken on Capital Bikeshare. Accomplished with a fleet of just over 3,000 bikes, our members have shown that bicycling can get you where you need to go all over this region. 

Based on the latest CaBi dashboard data cyclists have ridden more than 14 million miles. That's quite a success and one that's good for the community. In addition to the health and mobility improvements, it means less pollution, and possibly less congestion, too.

A recent study claimed that bikesharing might actually contribute to congestion and pollution because of the rebalancing vehicles. I'm much more confident on pollution than I am on congestion. Based on the latest CaBi member survey, we can see that the CaBi results in the following mode shift.

37% - Shift from walking to bikeshare

6% - Shift from driving 

6% - Shift from Taxi/uber/lyft

40% - Shift from bus, metrorail

3% - Shift from no trip

I'll ignore the 3% other and the 5% who would've rode their own bike. 

On pollution, we can see that 12% of trips switch from cars to bikes. If year 2 data is applicable, we know that every 10 miles of biking requires 1 mile of rebalance car driving. Looking at this simply, it means that every 12 miles of driving shifted to bikeshare is offset by 10 miles of rebalance vehicle driving. Now, it's likely that the trips shifted from driving were longer than those shifted from walking, but also that the rebalancing vehicles use more gas than the average passenger car, so it gets more complicated in reality. But still I think it points to a modest reduction in pollution from driving alone.

And of course, taking 3.7 million people off of transit should reduce pollution too. Even if you think it means that no fewer buses or trains are needed, carrying extra people requires extra energy. And for buses at least, extra passengers mean more stops. I think it's pretty clear that when all of this is considered it's very likely that bikeshare reduces pollution.

Congestion mitigation is less clear

Using 1 unit of congestion as that which is caused by a car, we can say that before mode shift motorists would've caused 12 units of congestion. While pedestrians and transit users would have caused less congestion than motorists, it wouldn't be nothing. More bus passengers means more bus stops and longer dwell time, and pedestrians delay drivers who are trying to turn at intersections. Unfortunately I can't find any study that defines a conversion factor for the congestion caused by these groups (nor does CaBi break out bus from rail). So, for now, we have unsolved variables x and y.

After the mode shift, we have 0.28 (the bike conversion factor) + 0.10 (Rebalancing vehicles drive about 1 mile for every 10 miles of biking) * 92 (the percentage of people shifted to bikes) which equals about 35 units. 

So, without knowing the values of x and y, I can't really say that bike share reduces congestion (or that it doesn't). And again, it gets more complicated, since I'm assuming that rebalancing vehicles drive at the same times of day as the bike share trips happen, which is pretty unlikely. To whatever extent rebalancing trips are shifted from rush hour, that reduces the congestion caused by bikeshare rebalancing.

It's still too early to make any statements about safety.

The death rate per 100 million automobile miles traveled in DC is 0.56, so while it's certainly good that there have been no CaBi deaths in the first ~15 million miles, that would be expected. Once CaBi has 500-600 million miles under its belt, we might be able to make some statements about its copmparative safety. Currently, this is complicated by the fact that CaBi estimates mileage, and while there is talk of using GPS to get a more accurate measure of mileage, no such data is available right now.

What we do know is that there have still been no deaths in the United States by bikesharing cyclists. And that report from last year was after 23 million miles, but there has been a lot of bikeshare miles covered since then.

There have been a few deaths elsewhere. One in Canada. One in Mexico. One in London. And then at least eight in Paris (3 of them in the first year). But certainly not enough to fear blood in the streets or 6 bikeshare deaths in New York by the end of 2015.

Here's looking forward to the next 10 million trips.

Comments

[SJE]

Interesting that the average trip is 1.4 miles, suggesting that there is a lot of "last mile" transit and short trips. It also shows that lots of people get on bikes for a quick trip, and that it does not have to be a major effort.

[Ampersand]

@SJE - The automatic capital bikeshare mileage calculator just takes the time a bike is out and multiplies by a super conservative base speed - something like 7 mph. For example, I've taken a trip from two stations that are physically 3 miles apart but according to bikeshare I only rode a mile and a half. So I'm thinking that the average trip is probably longer than their estimate, although I'd also believe that there is a ton of last mile usage.