Sometimes I tweet things that get pretty popular and then I need to go into more details. Case in point:

Which I followed by tweeting:

Knowing how many miles of bike lanes you have has little importance in determining if I’m going to bike in your city when I visit, or if I’m considering moving there, or if I want to add you to a “bicycle friendly cities” list.

What’s more important is how much the number of people bicycling on those bike lanes has changed. This number will reflect the quality of your bike lanes. Are they still in good shape or have they faded a lot? Do they connect to each other to create a network, or are there gaps that increase the stress of a route? How have you treated the bike lane at intersections, the place where a conflict and crash is most likely to occur?

Chicago Tribune architecture critic Blair Kamin touched on these points in his recent critique, one of the few worthwhile articles the Tribune has published in the last year about bicycling, by interviewing an organization that tries to make it politically palatable to build unconventional – in the United States – bike lanes.

“Chicago has made incredible progress over the last few years,” said Martha Roskowski, vice president at People for Bikes, a Boulder, Colo.-based advocacy group. But, she added, “Chicago also has a ways to go.”

That’s saying it nicely.

Addressing the gaps in the city’s network of protected bike routes, Roskowski said: “People evaluate a potential bike ride on the basis of the weakest link, the scariest part of the trip, which might be a really busy road you have to ride along or across. People have tolerance for a little bit of that. But if it’s sustained or if it feels dangerous, they just won’t do it.”

Enter Close Calls, deteriorating bike lanes, bumpy pavement, and constant obstacles and you get Chicago’s ridiculously low bicycle commute to work numbers.

Since Emanuel took office in 2011, Chicago has installed 52 miles of protected bike lanes [it’s only installed 16 miles of protected bike lanes], which use a variety of means — plastic pylons, striped pavement markings and non-curbside parking spaces — to separate bikes from vehicles. That brings the city’s total bicycle lanes to 207 miles.

That’s cool that we have 207 miles. How many miles of streets without bike lanes do we have? It’s 4,000 and some change minus 207.

Why doesn’t Mayor Rahm Emanuel talk about how many people have taken up bicycling since he took office, or how many more trips Chicagoans made (and where) because of those 52 miles of new buffered and protected bike lanes?

He can’t say how many people are riding their personal bikes because the city doesn’t track this.

Conversely we can track Divvy bike-share use down to the minute and the company announced that Saturday, May 24, they had their most trips ever. Only to be eclipsed by almost 4,000 more trips on Sunday, May 25 (helped in no small part by the Bike The Drive event where people can bicycle on a Lake Shore Drive that’s closed to vehicles).

In another blow to good data for Chicago, Divvy will only be releasing trip data twice a year, while Citibike in New York City will be publishing it monthly, an improvement of Capital Bikeshare’s quarterly data releases.

If you’re not tracking who’s using your infrastructure, will you be able to know if the people you set out to attract have come out?