National Roads in Greece

Highways in Greece are generally organized so that the odd numbered highways are of north-south alignment and even numbered highways are of east-west alignment. However, there are many exceptions.

The designation of some important roads of Greece as "national" was decided by a 1955 decree, while a minister's decision in 1963 determined the numbering of these roads. In 1998, a survey of the Hellenic Statistical Authority defined some new national roads that were constructed after the 1963 decision. Furthermore, motorway numbers in Greece are different and irrelevant to other highways' numbers. For example, Motorway 6 (A6) refers to the Attiki Odos motorway, while "GR-6" refers to a different road.

Greece's motorway network has been extensively modernised throughout the 2000s and part of it is still under construction. Most of it is expected to be completed by early 2017. There are a total of 10 main routes throughout the Greek mainland and Crete, from which some feature numerous branches/auxiliary routes, as described in the listing below.

Motorway 1 (A1), colloquially referred to as the PAThE motorway (derived from the initials of the route: Piraeus – Athens – Thessaloniki – Evzoni (the border crossing with the Republic of Macedonia)); is the oldest and most important motorway of Greece, connecting the country's largest cities, Athens and Thessaloniki and passing through many important regions of Greece on a south-north direction. Most of the route has been upgraded to motorway standards, expept for some kilometres between Halastra and Polykastro

As of summer 2008, works were in progress around the Malian Gulf, due to be completed in 2010. Most of the route around the bay, was completed in April 2008, but due to delays, the last part (the 17 km Stylida-Karavomylos bypass) was finally given to traffic on March 16, 2015. At Tempe valley, works started in 2008, in order to be completed around 2012, but due to severe delays they were completed in April 2017. This part includes 11 km of tunnels, made mostly for environmental protection and, of course, road safety. Furthermore, the section between Thessaloniki and Evzoni, is yet to be converted into motorway, but this is not planned to happen in the near future.

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