Opened on 5 December 1958 by Harold Macmillan, prime minister at the time of its inauguration, the by-pass was described by The Engineer as ‘of special significance’ due to its status of being the first road in the British Isles for motor traffic only, designed to full motorway standards and eventually forming part of what would become the M6.
The road was of special interest as an achievement in civil engineering construction, with its design described as being ‘as modern in concept as the traffic aspect, set out to take the maximum advantage of mechanised constructional methods.’
https://www.theengin...ch-of-motorway/
Opening of the Preston By-pass Motorway :-
https://theengineer..../12/Dec1958.pdf