Preston By pass

Planning

Before the motorway was constructed, the A6 road through Preston handled all traffic with tailbacks and congestion a common occurrence, moreso during special occasions such as the Blackpool Illuminations. The route had been planned as far back as 1937, with the basic alignment envisaged from that time still feasible by the time Lancashire County Council gave approval in the mid 1940s. At this time, the legal powers necessary for motorway construction did not exist, until the introduction of the Special Roads Act in 1949 that provided the legal powers to construct a motorway. The motorway was seen as an experiment for future motorway construction with many lessons and techniques learnt that would help towards successful future motorway construction. Following the proposals being made public, only a handful of formal objections were raised, which were resolved by agreement without the need to initiate a public inquiry, cited in part because of close personal involvement of Lancashire County Council and the surveyor during the process of consultation.

The Tarmac Group (now Carillion) were successful with their bid in 1956 to construct the new motorway, including 19 of its bridges; John Cox was the onsite engineer assigned by the contractor to oversee the construction.

Construction

The road was originally built with two lanes in each direction, but with an unusually wide central reservation to provide provision for a third lane to be added each way at a later date. The widenining of the central reservation was reached as a compromise between Drake and the Ministry of Transport, the latter whom deemed 2-lanes in each direction as being adequate. Initially, the shoulders were hardened with gravel but not paved, a fact still reflected in the British term hard shoulder. A hedge was planted along the length of the central reservation to help reduce dazzle from the headlights of oncoming traffic at night. The road was constructed to not be a long length of straight road and with the addition of various bridges and tree planting, in the hope to prevent driver boredom that was understood to have been reported on foreign motorways.

The earth material used for the embankments was initially proposed to come from excavated material collected from the road foundation works, however the rainfall meant the material was no longer suitable for this purpose and instead had to be imported. In total, 3,400,000 tons of earth was excavated, with a further 668,000 tons of material imported for filling. The sub-base consisted of burnt red shale with thickness dependent upon the ground conditions, followed by a layer of wet mix around 9 inches thick and topped with 2–3 inches of tarmac lined with 0.5-1 inches of asphalt. There were a total of 22 bridges planned for the entire length of the by-pass and designers were given relative freedom in creating innovative designs. Chief engineer Drake proposed that the bridges should be painted a variety of different colours, contrary to conventional practice of using neutral colours as he believed this would enhance aesthetics but more importantly, help to ensure driver boredom was alleviated; driver feedback to alternately coloured bridges subsequentally received a favourable reaction.

The contracted period for construction was envisaged to be in the region of two years, however the initial timescale was lengthened by nearly 25% due to rainfall that persisted throughout much of the early construction period. The heavy rainfall through the autumn of 1956 had profound effects on the heavy engineering works required to construct the road foundation, resulting in this aspect of work being postponed until the following spring in 1957; an extension of five months was granted due to the extraordinary and unforeseen weather conditions. Numerous lessons were learnt from the construction of Britain's first motorway, not least relating to usage of an appropriately screened base material, with water drainage systems that should be appropriate and fit for purposes, as well as the inclusion of continuous hard shoulders to name a few.

Opening

The by-pass was opened on 5 December 1958 by the Prime Minister, Harold Macmillan at a cost of £2,960,481 (equivalent to £62,376,169 in 2015), of which almost £2.5m was for constrution of the motorway itself and over £500,000 was for the construction of two required major bridges, those being the Samlesbury Bridge (£334,431) and the High Walton Bridge (£193,690) respectively. Macmillan became the first man in Britain to travel on a motorway, as a passenger in an Austin Sheerline limousine, setting off from what is now junction 31 on the M6 motorway. Many hundreds of people gathered at the interchange in Samlesbury to witness the official opening, of whom many had participated in the construction and were proud of what they had achieved.

Operation

The motorway was designed to be capable of handling vehicles at speeds of 70 mph (110 km/h), a limit which is unchanged to this day; however upon opening there was no speed limit enforced for the first few years. Shortly after opening, the motorway saw its first motor accidents, though both were minor incidents with no significant injuries; each accident was as a result of inexperienced drivers (in one case, an underage driver) being unfamiliar with motorway driving and losing control of their respective vehicles.

On 21 January 1959, just 46 days after opening, the motorway had to temporarily close to undergo emergency resurfacing work, as water had drained into the hard shoulder then seeped into the base layer which subsequently suffered as a result of frost weathering, resulting in crumbling road parts along the surface.

Upgrades

An additional 3rd lane was added in each direction in 1966 using the land reserved within the central reservation, without the need to modify the existing bridges. Despite the relative ease in the addition of a third lane each way, the lack of hard shoulders at the bridges meant the number of available lanes during engineering works was inadequate to cope with the traffic volumes of the time, estimated to be have been in the region of 140,000 vehicles daily.

The bypass underwent a significant reconstruction during the early 1990s, when it was expanded to become 4 lanes in each direction, with the entire carriageway being reconstructed to facilitate this. It was necessary to remove of all the original bridges after just 30 years in order to provide a 4-lane carriageway with a continuous hard shoulder, despite the bridges being constructed with an expected lifespan of 120 years. The bid to undertake the work was awarded to Balfour Beatty in February 1993, at a cost of £37,458,986 (equivalent to £68,813,271 in 2015). The substantialness of this upgrade meant that the bypass was entirely reconstructed and is now effectively a different motorway to the bypass that opened in 1958.

Route

Despite the motorway passing through industrial areas, the proposed route alignment meant that property demolition was kept to a minimum, with just a single farmhouse and three dwellings requiring demolition to facilitate construction. The route was constructed through four separate localities, including 1.65 mi (2.66 km) through the County Borough of Preston, 2.54 mi (4.09 km) through the Urban District of Walton-Le-Dale, 1.77 mi (2.85 km) through the Urban District of Fulwood and 2.30 mi (3.70 km) through the Rural District of Preston. The overall width of the motorway was 112 ft (34 m), 24 ft (7.3 m) for each carriageway, 14 ft (4.3 m) for the verges and a 32 ft (9.8 m) central reservation.

The route of the original by-pass is included as one of the most congested in the country, with traffic to and from Preston being labelled amongst the country's top 25 most congested routes.