dtgreene: I thought of another question:
In the US, there is an interstate highway system, with a bunch of highways being numbered; I believe this numbering goes from 1 to 95. North-south highways are given odd numbers, and east-west highways even ones. Do other countries have similar systems?
Related question: Does the EU have a system of naming or numbering highways that is consistent between the member nations?
Can't tell for the whole EU, but:
The German motorways are numbered according to a clear system. Since the mid-1970s, there is a numbering system for motorways, which approximately specifies which number a new highway receives. Federal motorways with a single-digit number (eg A 1) are of nationwide or even cross-border significance. Highways with two digits as a number (eg A 20) are usually of overriding regional importance. Highways with three digits as a number (eg A 999) are typically of regional or city significance. Often these highways are feeder roads or detours.
For highways with more than one digit, the first digit indicates the approximate location of the motorway:
1 = Greater Berlin, Leipzig-Halle, Dresden,
2 = Greater Hamburg,
3 = Greater Hannover / Bielefeld / Osnabrück,
4 = Greater Ruhr area / Kassel / Rhineland-Palatinate,
5 = Greater Cologne,
6 = Greater Frankfurt am Main,
7 = Greater Schweinfurt / Nuremberg / Erfurt,
8 = Greater Stuttgart,
9 = Greater Munich.
With the exception of southern Germany, the distribution is analogous to the distribution of the first digit of the four-digit postal codes valid in Germany until 1993.
As a rule, motorways with even numbers run predominantly in the west-east direction, those with odd numbers in the north-south direction. Exceptions to this are, for example: the A 14 and the A 15.