The major E roads is spread over EU and allso called Europe roads, actually i did think myself that the roads had individual numbers in each country, but i have just been looking at google maps and "our" E 45 ends wayyy down in Italy actually on the island sicily at a town called Gela.
And E45 go way North too, i expected it to end in Northern Jutland at a town called Fredrikshavn, but it seem like the road take the ferry to Sweden as it continue over there and end way north at the Sweden / Finland border.
All in all E45 is 4,998 km (3,106 mi) long.
Here the E is just used on our largest and fastest roads, motorway / freeway / controlled access highway ( 110 - 130 km/h )
We have 5 E roads here in Denmark, the sign for them is green with white lettering and a white edge.
Our smaller highways / primary routes allso have numbers, for instance here around my home town Randers we have route 16 - 46 and 21, the speedlimit on the smaller highways is 80 km/h in general.
We have about 40 primary numbered routes, the sign is yellow background and black lettering and frame, nornally these are 1 lane in each direction, divided with a white line in the mittle of the road.
Like all other it can allso figure on a information sign like this, turn Right onto route 8 with 36 km to the town of Tønder.
We allso have secondary route numbers, these are like the primary route signs but with whire background, we have about 150 of those, normally just 1 road not having a center line dividing it into 2 sepearte lanes.
it can allso figure on a information sign like this. ( 3 digit or O1 / O2 indicating a road that bypass a major town, we allso call O roads "ring roads" as they are normally circular in shape )
I might be messing up with the US / English roadnames, here the fastest roads is called
motorvej in Danish, and the smaller highways
Landevej ( vej meaning road in Danish )
http://en.wikipedia.org/wiki/International_E-road_network