Interstate System? Europe laughs at your petty Interstate System, America. In 1975, the United Nations Economic and Social Council’s Economic Commission for Europe ratified a document outlining international traffic arteries through Europe and beyond. Commonly known as E-Roads, these highways criss-cross Europe in much the same way that the Interstate system does the United States, but with even more roads and even longer routes.

However, this system is overlaid on the top of national highways with varying levels of acceptance and success. The UK, while a signatory to the agreement, does not signpost E-Roads at all, while other countries have brought their national numbering totally in line with the E-Road system. As such, knowledge of this system is not universal and it often appears that there is a theoretical concept of a Pan-European highway system as opposed to an actual network of highways.

I actually started this diagram almost as soon as I finished my Interstates as London Underground diagram, and originally worked it up in exactly the same style as that piece (see image 4 above).  However, I soon realised that the European system’s extra complexity was not suited to that particular graphic style and put the project on the back burner while I pursued other diagram-related projects.

In August, I decided to start the project completely from scratch with a new, more precise style — a culmination of all the things I have learned creating all my transit-styled diagrams up to this point. The results were immediately more rewarding: the whole diagram hangs together much better this way and I couldn’t be happier with the end result.

To give you some idea of the work that I’ve put into this diagram, here’s a short time-lapse video of its construction in Adobe Illustrator. Each shot is taken roughly 30-45 minutes apart.

As usual, comments and corrections are welcome.

And finally, a couple of notes:

• Ferry routes shown are as listed in the United Nations agreement document, and do not necessarily correlate to an actual, existing ferry route. Some existed in 1975 and have since shut down, others have never existed at all except in theory.
• Amsterdam is the capital of the Netherlands, The Hague is the seat of government.
• E04 through Sweden is coloured as if it is a continuation of E55. This is intentional, as E04 is E55 in all but name. By the time the route of E55 was decided upon, Sweden had already signposted the entire length of the designated road within Sweden as E04 from an earlier system. To save the expense of new signs, Sweden was allowed to keep the E04 designation.