Hacking Seattle’s Bike Share, Part 1: Hills and rain

This is part one of a series looking at the first year of usage data from Pronto Cycle Share. Pronto organized a "data challenge," and the submissions they received go deeper than you might expect.

Did you know there are hills in Seattle? And did you also know it rains here kinda often?

It's true, and there are bike naysayers who say investing in biking is pointless because people won't bike up hills or in the rain. And sure, these are certainly factors in whether people choose to make a trip by bike, but there are still a whole lot of people who are not deterred.

Jake Vanderplas, a West Seattle safe streets advocate and very smart person, entered a lengthy analysis of Pronto trip data that earned him the "Most Insightful" award in the organization's recent Data Challenge. And he found that both hills and weather affected bike share trips just about how you would expect.

But first, we have to separate two kinds of users: Annual members use bike share like a typical transportation system, so you see more traditional commute patterns with peaks during the morning and evening rush hours. If it's a weekday, the vast majority of riders are members using the bikes for "regular" transportation.

On the other hand, short term pass holders are more likely to be making a non-commute trip, and many of them are probably visitors or locals giving the system a try. On a weekend, the majority of trips are made by short-term users.

It makes sense that short-term pass holders would not follow a commute pattern, since the system's membership pricing structure heavily incentivizes buying a membership if you like using the system. At $85 for a whole year, you make your money back after only eleven days of use.

Temperature is a bit of a tricky issue, especially for short-term rentals. After all, warmer months are also summer vacation months, so it's a little hard to know exactly where the temperature effect on trips ends and the time-of-year effect begins. But in general, there are few surprises here. People take more trips when it's warm out. People take fewer trips when it's rainy. But outliers aside (like major storms), a lot of people bike even on cold and rainy days.

Annual members are more likely to bike through bad weather, but someone is more likely to think twice about spending $8 to bike in the rain. That also makes sense.

Annual members have also figured out that they don't need to bike round trip. That means there are a bunch of downhill bike share trips that don't come back up the hill (perhaps they just walk, take the bus or ride share?). In fact, 63 percent of annual member trips are downhill. This also makes sense, and Pronto knew this was going to happen. That's why they have staff rebalance the system by driving bikes from overloaded stations to mostly empty ones.

But what surprised me is that short-term pass holders are much less likely to bike downhill without returning their bikes back uphill. Only 44 percent of these trips are downhill, and a much larger share of them are "flat trips," often round trip rides that return a bike to the station it came from. This fits with, for example, a bike ride from the cruise terminal to Myrtle Edwards Park and back.

However, more than a third of trips are uphill. So don't believe people when they say people won't bike uphill. There were 140,000 trips in the system's first year, so that's about 47,000 uphill bike trips. That's not too shabby.

And this brings us to another entry in the Data Challenge by Bailey Harper and Chris "Feckless" Jambor, who have some interesting ideas for how to help correct this pattern.

One easy way, which has also been tossed around previously on this blog, is a time bonus for biking uphill. They found that every 100 feet of elevation gain adds about 2 minutes. A mile biking uphill adds 11 minutes, and uphill trips take 18 minutes longer than the average trip systemwide. Since overage charges kick in after 30 minutes, the pricing structure actually incentivizes NOT biking uphill. So what if uphill trips got 15 minutes added automatically? This could, for example, give enough time to bike from UW to Capitol Hill, a trip that currently you can only really make in time if you are headed downhill.

But Bailey and Chris go a step further, suggesting that Pronto could create a game out of it. What if you won stuff for biking uphill enough? Users could receive, say, a free 24-hour guest pass once they bike 605 feet uphill (the height of the Space Needle). Prizes can scale up and up until you get to, say, Mount Rainier at 14,409 feet, when you win a free membership for your next year. After all, at that point you have effectively rebalanced 35 bikes, which provides the system value. The numbers may need to be higher or subtract your downhill trips, I don't know exactly. But it's certainly worth exploring. This could also be turned into a fun marketing opportunity.