Planning started in 1937, despite the lack of legal powers permitting motorway construction until the introduction of the Special Roads Act 1949.

Weeks after opening, the road had to close temporarily due to water causing other problems when the base layer was damaged by a rapid freeze and thaw cycle.

As a result, the oldest surviving British motorways today are the M1 (between junctions 5 and 18) and the full length of the M45 which both opened one year after the Preston Bypass.

[1] Before the motorway was constructed, the A6 through Preston handled north-south traffic, leading to frequent tailbacks and congestion, especially during special events like the Blackpool Illuminations.

In 1938, Chief Engineer James Drake was part of a delegation from Lancashire that travelled to Germany to gather insights for the plan.

These were resolved amicably, largely due to the close involvement of Lancashire County Council and the surveyor during the consultation process, eliminating the need for a public inquiry.

To combat driver boredom, the design included curves, various bridges and tree planting, avoiding long, straight stretches.

[4] During early construction, some land was unavailable due to 75 agreements with landowners, including clauses allowing farmers to complete their harvests before work began.

[8] The initial plan for the embankments had to be adjusted; excessive rainfall rendered the earth unsuitable, leading to the importation of hundreds of thousands of tons of hard fill from around Lancashire.

[5] Originally scheduled for two years, the construction period was extended by nearly 25% due to persistent rainfall, particularly in late 1956, which delayed critical foundation work until early 1957.

[8] Valuable lessons were learned from the construction of Britain's first motorway, particularly towards using an appropriately screened base material, effective water drainage systems and the inclusion of continuous hard shoulders.

[13] The Coventry Evening Telegraph suggested in the first weeks after opening that the motorway was losing several hundred pounds a day, factoring in the lower than expected usage compared against the construction cost.

[17] On 21 January 1959, just 46 days after opening,[6] the motorway had to close temporarily to undergo emergency resurfacing work, as water had drained into the hard shoulder and seeped into the base layer.