A signpost marking the directions of north and south has been placed at the Watford Gap Motorway Service Area on the M1 motorway
The M1 is 50 years old, with the event being marked by the unveiling of a plaque at the motorway's most-famous service station.
Roads Minister Chris Mole will perform the unveiling at the Watford Gap services in Northamptonshire.
The first section of the 193-mile road was officially opened by the then Minister of Transport, Ernest Marples, on November 2 1959.
That first 62-mile stretch ran from what is now junction 5 near Watford in Hertfordshire to what is now junction 18 near Rugby in the West Midlands.
Mr Mole said: "I am delighted to mark the 50th birthday of the M1 - a motorway with an iconic past which will soon benefit from the latest in motorway modernisation thanks to Government investment of up to £6 billion.
"The M1 is a key artery, impacting upon both national and local economies, moving goods and people to places around the UK, while supporting investment."
Paul Watters, head of road and transport policy at the AA, says: "The significance of the M1 can't be underestimated - it is the backbone of the UK. It revolutionised travel as Britain's first long-distance motorway - before it opened, you'd be lucky to get to the Scottish border within eight hours from London but now you can be halfway up Scotland in that time."
He went on: "We should never under-invest in this key part of British life and the economy - it is arguably, in communication terms, our most important motorway."
The M1 was originally designed to take around 13,000 to 20,000 vehicles a day, but now accommodates between 140,000 and 160,000 a day.
