The building of motorways wasn't made possible until the passage of the Special Roads Act, 1949, through Parliament. A four-lane motorway had been proposed for the north-west as early as 1924 but the idea was dropped after pressure from railway lobbyists.

The Preston Bypass was designed by the staff of (Sir) James Drake's office. He was Lancashire County Surveyor. Its first incarnation was as a two-lane motorway with hard shoulders.

Drake thought this insufficient, so ensured that the central reservation was wide, and, indeed, this was was used up when the road was widened to three-lane in 1965-66. The hard shouders did not continue under the overbridges at this time.

In the 1990s, the motorway became four-lane with continuous hard shoulders, thus requiring the building of new bridges across it.

One notable feature: Junction 32 at Broughton (January 1965). This is the first three-level interchange completed in the UK.

Contractor: Tarmac Ltd