Your English: Idioms: run

A recent survey in the UK showed that traffic peaks during the morning rush hour are greatly exacerbated by the school run (the journey by car to school each morning). Some school run journeys are as short as 200 metres. One wonders whether the drivers shorten their journeys even more by using a rat run (a small road drivers use at busy times to avoid traffic on main roads).

In the normal run of things (as things usually happen) such journeys are probably not a dry run (something you do as a practice before the real event) and it is unlikely that the gas-guzzling drivers will have a clear run (be in a situation where nothing stops their progress). In the long run (not immediately but at some point in the future), such journeys will be counter-productive as it will clearly be quicker to walk than sit in a traffic jam.

In a different context, a run on something is when a lot of people want to buy a particular product at the same time, as in ‘There’s always a run on sunglasses at this time of year’, or a situation when a lot of people take their money out of a bank at the same time, as in ‘Nervousness from investors has led to a run on some banks’. There can also be a run on a particular currency if large institutions or governments start selling it in large quantities, as in ‘Fears that Greece may default on its debts have led to a run on the euro’.