The use of the term ‘roadmap’ to refer to a recognisable action plan or strategy has become firmly embedded in our everyday language. A 'roadmap to peace', a 'roadmap of financial recovery', for example, is used to describe something that has been coherently formed rather than scribbled on the back of an envelope.
Although the origins of the use of the phrase ‘to map’ in a planning sense is obscure (as indeed is the word ‘map’ itself as Matthew Edney has recently reminded us), its use does seem to have increased in recent decades in politics and the media. But how does the idea of a ‘roadmap’ (to recovery, peace etc.) align with the act of actually using a road map to get from, say, Milton Keynes to Ullapool in a car?
The earliest ‘road maps’ we know of were probably not originally intended to accompany an actual journey, though the information collected from first-hand travels would almost certainly have contributed to their compilation.
One of the earliest surviving road maps, The Roman Tabula Peutingeriana or Peutinger Map (a 13th century copy of a lost 4th century original, now in the Österreichische Nationalbibliothek in Vienna) shows the network of roads across the Roman Empire between south east England and India. It was more likely to have been used to plan, strategise and even commemorate, than to physically accompany a journey.
In a similar way, Matthew Paris’s famous itinerary maps of Britain, Europe and the Middle East from the mid-13th century were probably intended to commemorate or record journeys rather than facilitate further ones. However, they would also have enabled people to perform ‘virtual’ journeys by using them in association with a form of mental pilgrimage.
The practical British ‘road map’ we recognise today can be said to have emerged from the second half of the 17th century, when a genre of increasingly compact books emphasising routes (mainly today's 'A' roads, mostly following the work of John Ogilby) began to be published.
By the early 20th century, thanks to the burgeoning level of mobility and map literacy, (discussed at length in our 2016 exhibition on mapping the 20th century and this book) the road map became one of the most recognisable and functional maps available.
The politician's use of the word 'roadmap' is therefore perfectly consistent with the probable original use of road maps to plan and strategise, before they came to be used for actual wayfinding. However, how 'roadmap' came to be adopted in this way is probably more likely attributable to the modern ubiquity of road maps rather than an implicit understanding of their original purpose.