How good intentions can have unintended bad consequences
A story told through Don Norman’s eyes.
A couple of years ago the city of Milano saw a revolution: public bikes. A good thing.
They needed places to park these public bikes, so they stole places from the private bikes parkings.
Now people with private bikes can’t find their old parkings easily. So they park their bikes wherever they find an affordance:
Some objects afford a safe parking.
While others don’t.
Because you can easily lift the locked bike and steal it.
These two last objects are also an anti-affordance: they prevent cars to park on the sidewalk. They’ve been put where the sidewalk has a gentle descent.
They were needed because the descent is an accidental signifier to crafty drivers. It communicates: you can climb the sidewalk here.
The sidewalk descent was made to afford ‘descending’ to wheelchairs, they were not made to afford ‘ascending’ to cars.
The unintended consequences
For people in a wheelchair sometimes a problem arises unexpectedly when the wrong object (the safe pipe) is used for a noble aim (preventing cars to climb the sidewalk) and an unexpected event occurs (no more private bikes parkings around): bikes become an anti-affordance for wheelchairs.
How do you prevent this from happening? I see two possible solutions: we could only use the unsafe pipe or create more private bikes parking around.