The spaghetti junction was designed in 1972 to carry 75,000 vehicles a day but it currently takes three times that.
The plan back then was to link the existing sections of the M1, the M5 and the M6 - and provide a major route in and out of Birmingham. Gravelly Hill, just north of the city centre, was chosen as the site and the M6 and A38(M) or Aston Expressway were the mainstays of the new junction.
But existing local roads also had to be incorporated - resulting in 18 routes spread over 30 acres. A Birmingham newspaper journalist likened the junction to a plate of spaghetti - and the name was born. Andy Bevan looks back at the history of the spaghetti junction.