Driving through France recently I pondered the E numbers (nothing to do with food additives) on motorway signs. They usually appear on signs together with an A number, see below. The A number is part of the French road numbering system but what about the Es?
I had previously seen similar green E number signs in Belgium and Holland so thought they were a “Brussels” type Euro-invention. But, if so, why have they not been forced on us in the UK?
Well, it turns out that the idea for these international road numbers pre-dates the EU, originating in 1950. They are a product of the United Nations! Specifically, the United Nations Economic Committee for Europe (UNECE), created in 1947, who issued a declaration on a European road network ( UNECE Declaration on the Construction of Main International Traffic Arteries, of 16 September 1950). Since then there have been several other UNECE initiatives associated with roads in Europe the major one being the European Agreement on Main International Traffic Arteries (AGR), of 15 November 1975 which entered into force in 1983 (obviously before spell checks were routinely used!). There have been several revisions since, the latest being dated March 2008 (http://www.unece.org/fileadmin/DAM/trans/conventn/ECE-TRANS-SC1-384e.pdf). As far as I can see while the UK and Austria have signed this agreement, neither has ratified it. This leaves us in something of a minority since thirty seven other countries have ratified it. I can recommend all of these revised documents very highly to anyone looking for an insomnia cure or as an appealing alternative to head-banging against a solid brick wall. They are extremely turgid!
The original UNECE idea appears to have been to emulate, in Europe, the interstate network of the USA (http://en.wikipedia.org/wiki/International_E-road_network). In both networks the roads have to meet certain quality criteria. In Europe these include aspects such as width of central reservations, maximum gradients and overhead clearance, and the numbering systems of both are systematic based on road quality and geographical features such as east-west or north-south orientation. For example, in Europe east-west roads of the highest standard have two digit numbers ending in zero and are numbered increasing from north to south. In the USA, east-west roads have odd, and south-north roads even numbers. In Europe, north-south roads of the highest standard have numbers between 5 and 95 all ending in 5. Not surprisingly, there are some exceptions to these strict geographical rules in Europe. (I do not think we in Britain can feel too smug about this. It appears that we have several roads with the same road numbers in different parts of the country, such as the A594 which is both a road in Cumbria and the Leicester ring road http://www.roadsuk.com/network/duplicate/.)
More surprising, to me anyway, is the fact that quality standards for some parts of the European network have not always been followed. Some roads in Sweden and Norway do not meet the width criteria and in Central Asia some gravel roads form part of the network. This may be because the designation of roads to the network is ultimately the responsibility of the national government. The AGR simply stipulates the major cities in the route of a given E road. Member states decide which of their roads will be used to achieve this itinerary So, for example, some E roads in Croatia are the old state routes not the more modern highways.
An example of a west-east orientated major road is the E30 which starts in Cork, goes via Rosslare and Fishguard, then goes to London up to Felixstowe and on to the Hoek van Holland. E30 eventually ends at Omsk in Siberia. An example of an north-south orientated road is the E15 starting in Inverness going via Edinburgh, Doncaster, London, Dover, Calais and ending in Algeciras.
The longest E road is the E40 starting in Calais and finishing 8,500km (5,300miles ) later in Ridder, Kazhakstan.
The shortest is the E844 in Italy which is just 22km (14 miles) long.
The highest is the E008 which reaches 4272 m (13500 ft) altitude in Tajikistan.
Many countries, like France, display the E road numbers alongside their own number. But some – Denmark, Norway and Sweden – use only the E road numbers in their national road network. Britain does not display the E numbers at all; a characteristic we share with Uzbekistan. In fact, the E30 actually takes the following UK roads; A40, A48, M4, M25, A12 and A14. So having the number E30 alongside the A and M signs might be quite confusing, I think.
In truth, the numbering seems a bit of a mess because sometimes E routes are shared. Thus the E20 in Sweden goes along the same route as the E4, E6 and E18 for part of the way. It is also a little misleading. If you were in your car and following the E30, for example, and reached Felixstowe intending to take a ferry to the Hoek van Holland, you would discover that there are only freight ferries available and you need to take another road to Harwich to find a passenger ferry. This would take you back on yourself for a further 53km (33 miles).
The E70, shown in the picture above, would also be impossible to follow for its entirety. It starts in Spain at Coruna and travels through France, Italy
Part of E70 in Italy
Slovenia, Croatia, Serbia, Romania, Bulgaria at Varna. From there the route crosses the Black Sea, presumably by ferry, to Samsun in Turkey and on, to end at Poti in Georgia 4550km (2830 miles) later. Unfortunately, there is no ferry operating between these places at present! (http://en.wikipedia.org/wiki/European_route_E70)
I suppose E routes and numbers are quite useful if you are driving on a route that takes you through several countries because you can keep following the same road number, assuming the different countries all display the E numbers. Although, with the growing use of satnav, even this is questionable. And, I can quite understand, and approve of, the UK stance of not adopting them into our road numbering system. Our roads, obviously, do not join up with those of any other countries, so they are of limited value and it would be very expensive now to add them to our signage.
seclectic 
E routes may have some benefit at the continental level where a sizeable number of drivers may frequently travel through several countries in a day ,often intensely populated countries [say Belgium, Luxembourg Holland and Germany ]. However many of the routes arguably don’t make much sense other than being N-S or E-W routes one a continental map – for example the numbers of people say wanting to drive from Algeciras to Glasgow must be minuscule. [ Also they can only get there via Southampton – most would probably fly !]
.Another problem, apart from Britain being an island, is that the EU routes don’t really reflect the most popular routes WITHIN the UK or or Ireland [ i.e the key routes between the largest population centres ] but between places/towns lying on either a north south or an east west grid which must end in a port allowing access to European continent . These are not necessity popular or heavily used routes routes. Thus there is a secondary E18 route from Newcastle to Londonderry via Stranraer – hardly a route of any significance whatsoever over in terms of UK traffic likely to use it . Ot there is the major e/w designated route the E20 from Shannon to St Petersburg[ via Dublin/Liverpool ferry ] and then Hull/Esbjerg ferry ] and Stockholm/Tallin [ ferry ]. Hardly route likely to be used from end to end . Equally there isn ‘t a single designated route from Glasgow or Manchester to London { a very busy route – indeed one of the UK’s busiest ] to get there you must use the E5, E24 and E13! – there is therefore no advantage over using using the UK routes number . Also other busy and important routes aren’t even designated at all : for example Birmingham -Bristol -Plymouth isn’t even on the map despite being very busy route the M5!{and Plymouth having ferries to Europe ] . In truth the numbers here don’t really reflect UK desire lines , are interrupted by ports [some do not have a car ferry to where the road goes t was well ].Using them would simply add an unnecessary layer of numbering in the UK and might actually create confusion .
Yes I was not implying we should adopt them simply exploring their origin and some of the less logical quirks. As you point out viewed from a UK perspective they are pretty useless.
I would comment first that Chris Fairlamb is incorrect in referring to the E-routes as EU routes; they are nothing to do with the European Union, and indeed predate the EU by a number of years. They were a post-war initiative of the United Nations Organization.
Second I can recall, rather vaguely, about seeing the E number on a route in the east of England about sixty-plus years ago. I have a feeling it may have been the E32, and the number appeared on a green strip added to the route panel on the old style, pre-Worboys direction signs. According to Wikipedia:
“Route E 32 in the international E-road network is completely within the United Kingdom.….
“The E 32 runs between Colchester and Harwich, and is 30 kilometres in length, making it one of the shortest E-roads. It follows the A120 road. In the western part it is similar to a motorway but not signposted as such. The rest is ordinary road. It carries a lot of heavy vehicles. It connects to the E 30 and to the ferries from Harwich to Belgium, Netherlands, Germany and Denmark.”