Photo: Antonio Perez/Chicago Tribune

Via Streetsblog Chicago's John Greenfield, here's a CDOT map of Divvy use on Wednesday, July 24. There are other visualizations out there, but it's nice to see point-to-point trips.

Map: CDOT via trapgosh/CC by 2.0

Not too many surprises: heavy Loop and lakefront usage, with lots of traffic to and from the Loop without as much from station to station outside of it. As Greenfield documents, there are distinct patterns between annual members and 24-hour pass users (likely tourists, but entirely plausible that it's locals outside the Divvy range, or day-tripping suburbanites).

24-hour usage spikes on the weekends (2,500-3,000 trips a day), while annual-pass usage actually falls on the weekends (from about a thousand per day to about 500). Which suggests that annual users are using it for or while at work more than for recreational use. But that could change as the network spreads out and becomes less Loop-focused.

Greenfield's co-blogger Steven Vance talked to WBEZ about Divvy data the other day, and has a good breakdown here. For the two time periods Vance has, Michigan and Oak is the most-used kiosk, followed by Lake Shore and Monroe, which both connect up to the lakefront path. Vance writes:

Membership enrollment is still concerning to me: From July 22 (when I wrote my post about enrollment rate) to yesterday (Sunday, July 28), membership enrollment rate dropped to 61 memberships per day, even as all these new neighborhood stations emerged. This brings the post-launch average to 66 from 67.

But D.C.'s system started off with a similar pattern: it added about 2,000 annual members its second month (September-October), after launching with 49 stations. Then it completely slowed down during the winter (adding 2,000 members from October to March). In February 2011, its system had doubled the number of stations, and membership almost doubled from March 2011 (6,287) to April (11,847).

After that, the pace slowed, and has remained pretty consistent. Here's what it looks like from August 2011 through May 2013:

I wouldn't be surprised to see a somewhat different pattern in Chicago: the winters are harsh here, but D.C. can be awful during the summer. For instance, the D.C. system added less than a thousand members from June-July in 2011 and 2012, possibly because D.C. is totally miserable then. Either way, it appears the real test of the system will be in the spring, when the weather gets nice and potential Divvy users emerge from their hibernation to see an expanded system next year.