and
E451 near
Frankfurt Airport The route numbering system is as follows: • Reference roads and intermediate roads, called Class-A roads, have numbers from 1 to 129. • North–south routes have odd numbers; east–west routes have even numbers. The two main exceptions are
E4 and
E6, both north–south routes. • The allocation of numbers progresses upwards from west to east and from north to south, with some exceptions. • Branch, link and connecting roads, called Class-B roads, have three-digit numbers above 130. • Reference roads are roads numbered 5–95 ending with 0 or 5 or having odd numbers 101–129. They generally go across Europe and are usually several thousand kilometres long. • North–south reference roads have numbers that end with the digit 5 from 5 to 95, or odd numbers from 101 to 129, increasing from west to east. • East-west reference roads have two-digit numbers that end with the digit 0, increasing from north to south. • Intermediate roads are roads numbered 1 to 99 that are not reference roads. They are usually considerably shorter than the reference roads. They have numbers between those of the reference roads between which they are located. Like reference roads, north–south intermediate roads have odd numbers; east–west roads have even numbers. • Class-B roads have three-digit numbers: the first digit is that of the nearest reference road to the north, the second digit is that of the nearest reference road to the west, and the third digit is a serial number. • North–south Class-A roads located eastwards of road E99 have three-digit odd numbers from 101 to 129. Other rules for Class-A roads above apply to these roads. • Class-B roads located eastwards of E101 have 3-digit numbers beginning with 0, from 001 to 099.
Exceptions near
Cassino, Italy In the first established and approved version, the road numbers were well ordered. Since then a number of exceptions to this principle have been allowed. Two Class-A roads,
E6 and
E4 were originally scheduled to be renamed into
E47 and
E55, respectively. However, since Sweden and Norway have integrated the E-roads into their national networks, signposted as E6 and E4 throughout, a decision was made to keep the pre-1992 numbers for the roads in those two countries. These exceptions were granted because of the excessive expense connected with re-signing not only the long routes themselves, but also the associated road network in the area. The new numbers are, however, used from
Denmark and southward, though, as do other European routes within
Scandinavia. These two roads are the most conspicuous exceptions to the rule that even numbers signify west–east E-roads. Further exceptions are: •
E67, going from
Finland to the
Czech Republic (wrong side of
E75 and
E77), assigned around year 2000, simply because it was best available number for this new route. • Most of
E63 in
Finland (wrong side of E75) • Part of
E8 in Finland on the wrong side of
E12 after a lengthening around 2002 •
E82 (Spain and Portugal, wrong side of
E80). These irregularities exist just because it is hard to maintain good order when extending the network, and the UNECE want to avoid changing road numbers. Because the
Socialist People's Republic of Albania refused to participate in international treaties such as the AGR, it was conspicuously excluded from the route scheme, with
E65 and
E90 making noticeable detours to go around it. In the 1990s, Albania opened up to the rest of Europe, but only ratified the AGR in August 2006, so its integration into the E-road network remains weak. ==Signage==