Washington DC Cycle Commuters Suddenly Appear
One of the striking aspects of the US bike share schemes thus far is that they have generally been dominated by weekend use. There has been some weekday use but not a large commuter morning/evening surge, like has been seen consistently in London. However Washington DC at least seems to have reached a turning point, with the characteristic commuter spikes starting to appear, and a post-pm-peak distribution of bikes that had a distinctly London-esque blue in the middle (few bikes in the centre of Washington DC) and red on the outside (presumably more residential areas).
As Washington DC is joining London’s characteristic commuter “tidal flow”, London itself seems to be moving away from that. “Casual” use combined with unseasonably hot and sunny weather here, has meant a “tourist” afternoon surge, always seen at weekends, is present on weekdays now too. This somewhat dilutes the evening commuter use, although the system still ends up quite unbalanced at the end of the day.
I’ve made a minor adjustment to my bike share map statistics (see the “graph” link) – namely the one on the current number of bikes predicted to be in use. I’ve removed this statistic now. Previously, this assumed that the highest number of bikes available in the preceding 24 hours indicated the lowest moment of use. This is the case if no bikes are marked as faulty (or no docks are added to/removed from to the system) – however it turns out this is a significant number, at least in London. When a bike is marked as faulty, at least on the London system, then both the bike and the dock are removed from the availability numbers. By plotting this on a graph, estimates can be made of the number of bikes being marked as faulty each day. At the moment, this seems to be about 5-10% each day for London. Such bikes then get taken to the workshop, fixed, and appear to be replaced en masse just before the morning rush hour:
So now I look at the minimum number of free docking spaces in the last 24 hours instead. This should avoid the poor numbers after a heavy day of usage, where several hundred still appear to be in use at around 2am, whereas actually they are just bikes that were marked as broken on that day, on the stands. I have instead replaced it with a statistic showing the proportion of docks that don’t have bikes in them. This is effectively the same statistic as before, but now I don’t make assumptions about the “baseline” value, i.e. when no bikes are supposedly being used. In other words, previously I was effectively substracting a percentage from this value, based on the baseline percentage. I’m no longer doing that subtraction.
[Update – Those missing the # number of bikes measure for Washington DC/Arlington can find it here. These measurements are carried out a different way – by looking at changes in individual docks.]