Greece Interstate 1 is one of the longest highways in Greece. The highway begins at Kifissou Avenue or north of the Bay of Phaliro up to Efzoni at the FYROM border which intersects with M1 . Until the Euroroads numbers were changed, the northern part from Efzoni to GR-2 was E5N , today, the entire stretch is run almost by E75 . The freeway is tolled with the exception at the Aphidna tolls southward. One toll booth has been abandoned
It used to have entirely a 2-lane highway and ended near Katerini, in the mid-1970s, it extended to Thessaloniki and to the FYROM border, the highway had 4-lanes. It was extended during construction in the north in the 1980s? and the south in the early and mid 1990s. In 1998, the freeway had 3-lanes up to north of Thebes, and up to the Tempe Valley with a few sections at western Magnesia somewhere in the late-1990s. In 2002, it extended up near the tunnel and bypasses Larissa leaving about 10% including the Tempe Valley being 2-laned until a tunnel opened to have all sections having four to six lanes.
The portion west of downtown Athens runs over the Cephisus river and Kifissou Avenue. From north of the boundary of Voiotia -Phthotis , up to near Velestino, the toll freeway runs enxt to the bays and gulf which is connected to the Aegean. North of the Tempe Valley up to the south junction of the E90 , it is passed on the northwestern side of the Aegean. Its total length is approx 520 km.
Several movies in the 1950s and 1960s were shot at several interchanges in the Athens area and one in the 1980s when a flying car ran over the toll barrier.
The toll freeway passes within towns and cities ordered from north to south includes:
- Attiki Odos (14th km)
- Ekali-Varympompi (17th km)
- west of Agios Stefanos (21st km)
- near Aphidna and the Apihdna toll booth/station
- Interchange to Malakasa
- Varympompi (northern part)
- west of Chalkida
- north and east of Thiva /Thebes
- near Atalanti
- east of Lamia (until the opening of a tunnel)
- east of Velestino
- near GR-6
- east of Larissa, until 2002, near Larissa
- the Tempe Valley
- east of Katerini
- east of Lidoriki
- junction of E90 /GR-4 (west)
- junction of E90 to Thessaloniki
- junction of GR-2
- near Palaiokastro
- west of Efzoni
The highway section of Highway 1 except for near the freeway passes through Kifissou Avenue and the Varympompi-Ekali interchange, followed by Alexandria , Palaiokastro and up to the FYROM Border.