The second great lesson of economics insists that there are always opportunity costs. A corollary of this is that because everything, but everything, has costs there is no such thing as a solution. There are merely trade offs and the best we can do is to get to the optimal set of them.

This is true of everything:

Green roads risk delaying ambulances, say parents of dead boy

Gareth and Candace Edwards want the Government to ensure council-backed road closures don't slow down 999 emergency services

It’s entirely delightful, we agree, to have pedestrian areas, cycling lanes, speed bumps, slow traffic and all the rest. It is also useful - at times at least - to be able to navigate the urban environment at some speed. Too much of the one - either way - limits our ability to have the other.

This should be obvious of course, we’re all adults and we all know this. It’s just that political management of whatever it is always has a very hard time understanding the point. If some is good then more is better - a rule in politics as it isn’t in life.