The great train robbery: why Britain’s rail prices need a rethink

Outside mathematics, the word ‘commute’ can mean two things. Mostly it refers to the act of making a daily journey between one’s home and work; more rarely it describes replacing one penalty with another — as in ‘the Home Secretary commuted the death sentence to one of life imprisonment’.

The curious may wonder why one verb is used in two different ways. The reason is intriguing. In the early days of rail travel, workers in Chicago could ‘commute’ the cost of a daily rail ticket into a lower price per journey by buying an annual, or ‘commutation’ ticket. The word commuting originally referred to the act of reducing your ticket cost, then later came to denote the resulting travel.

This lexicographical leap contains an important lesson. It hints at the extent to which changes in human behaviour can be led by innovations in pricing.