European route E18 runs between Craigavon in Northern Ireland and Saint Petersburg in Russia, passing through Scotland, England, Norway, Sweden and Finland.

Although the designation implies the possibility of a through journey, this is no longer practical as there are no direct car ferry crossings between the United Kingdom and Norway.

[1] The route starts in Northern Ireland and runs from Craigavon (M1) – Belfast (M2, A8) – Larne, then to Scotland: Stranraer, Dumfries and Galloway (A75) – Gretna – then England via the (M6) – Carlisle (A69) to Newcastle.

It runs Kristiansand – Arendal – Porsgrunn – Larvik – Sandefjord – Tønsberg – Horten – Drammen – Oslo – Ås – Askim – Ørje (at the Swedish border).

A flyover carrying the E18 Holmestrand bypass, opened in 2001, partially collapsed in February 2015 following a landslip, necessitating its demolition and reconstruction.

[6] The situation has since 2009 improved thanks to increased capacity, and a new parking lot constructed by 2016 is expected to solve the problem for good.