I heard a wonderfully succinct specification of the congestion charge yesterday:
Every car which enters central London and does not pay £5 by midnight should be charged £40.
I like it both for its brevity and (which probably says something about me) for the fact that what most of us see as its core characteristic is relegated to a subordinate clause – a neat inversion of the expected way of describing it which is what allows for the economy of words.
It was being presented as a perfect project specification, “something an engineer could work from” (which in the context was the highest form of praise), and a reason why the system was delivered and did what it is supposed to. It is impressive just how much is captured in fewer than twenty words – but something absolutely fundamental is missing.
I wrote a few weeks ago about the emotional experience of dealing with the congestion charge:
TfL assumes from the outset that non-compliance is an attempt at evasion and its first response is to impose punishment.
Technically, the congestion charge seems to work flawlessly. But the relationship it assumes with its users is somewhere between condescending and insulting. That’s not in the one sentence spec – but just as importantly, it’s not obvious that it’s missing if you start with a purely functional approach to service design.