The central problem

A once famous question posed to job-seekers at Microsoft was ‘Why are manhole covers round?’ The question was revealing not because there was a single right answer, but precisely because there wasn’t. It helped elicit whether the applicant was someone happy to supply one plausible answer or someone who looked beyond the obvious.

At a simple level, manhole covers are round because manholes are round. But there are other reasons. A circular manhole cover cannot fall down the hole beneath; a square manhole, if aligned diagonally, could. Round manhole covers can also be moved easily by rolling and replaced in any orientation. They are probably stronger than square ones. And so on.

Equally good is the question asked of economics students by Professor Robert Frank at Cornell. ‘What happens to the price of pork if the price of pig-feed rises dramatically?’

Counterintuitively, in the short-term it would fall. This is because farmers would stop fattening up more mature pigs and release them to market earlier, causing a temporary pork glut. Now the EU has kindly given us material for an even better question. It has mandated that from 2022 new cars be fitted with speed-limiting technology. An on-board video camera can recognise speed limit signs and, in conjunction with GPS-linked speed limit data, enact a system that actively limits the vehicle’s speed.

It would make a very revealing interview question: ‘How might this technology be used intelligently and how, if badly implemented, might it be dangerous?’ Bonus marks (as with the pig-feed) for anyone who suggested that the short- and long-term effects might be different.

In defence of the EU, it has simply mandated (for now) that the technology be installed, not how it is deployed. It may (for now) allow drivers to override it when overtaking.