The bike parking at Tate Modern is an interesting case study. They've provided a perfectly decent bike shed less than 40m from the main entrance. That's not far. You could throw a pot of green custard further than that.
But nobody ever uses it (top right). I was there last night and, like everyone else (below right) I parked my bike on the railings that lead up the slope to the main entrance.
Similar effects can be seen everywhere. Many supermarkets, for instance, put cycle racks off at the other end of the car park, with the result that trolley-park railings, being next to the entrance, are pressed into service as impromptu Sheffield stands.
We're not being contrary or ungrateful. It simply goes to show that we expect cycling to be a door-to-door activity. That's the beauty of it.
Another element is probably psychological. There's something open and obvious about a bike. Unlike a mobile phone or a collateralised debt object or Microsoft Word's file-saving format, it's perfectly clear how it works. You can see all the cogs and wires in front of you and how they all join up. A hitherto uncontacted Amazonian tribe with no knowledge of fabulous modern technology such as polyphonic ringtones would grasp a bike's mechanical principle at a glance.
That straightforward, take-me-as-you-find-me concept often applies to cyclists as well, who are usually unpretentious and down-to-earth. (Though I'll grant you, racers and couriers can be a bit bonkers.)
So I'm sure that's another factor behind the Tate Modern Effect. The bike shed's not far, but it's concealed, out of the way, out of my psychological control zone. The railings are right there, open, accessible and visible. And other people are already parked there, too. (As with restaurants, we're more likely to opt for the place that's already populated over somewhere empty.)
Memo to planners: Whatever the artist's impression might have depicted, we'll go for the street furniture by the way in over a five-star bike park round the corner every time. In the world of bike parking, 40m is a long way.