Lancashire motorway bridge demolition plan dropped because of rocketing costs

Lancashire County Council’s cabinet agreed to remove the structure – which carries Higher North Road in Carnforth over the A601(M) – back in July 2020.

The project was part of a wider planned scheme to address the long-term maintenance needs of the route, including several other bridges across the 1.3 mile-long road, which connects the M6 at junction 35 to the A6 north of the town.

County Hall also decided to apply to the government for permission to turn the mini-motorway into an “all purpose” route in order to reduce the upkeep costs associated with the stretch because of its status at the top of the roads hierarchy.

However, cabinet members recently gave the green light to a rethink of the plans after hearing that the ballooning bill for the work was likely to exceed the £9.2m budget set for the overhaul, which is being funded by a Department for Transport grant.

The discovery last year of the need to re-route a high-pressure gas main had threatened to add £3.5m to the cost of the scheme, which was already beset by rocketing construction costs as a result of recent rises in inflation. The diversion of the gas pipe would also have pushed back the start date of the work to this summer at the earliest – risking a further price escalation in the meantime.

The original option of removing the bridge would have required a new graded, traffic light-controlled junction to be created at the point where the roads would then meet. That was always going to have a much higher upfront cost than the alternative of carrying out the immediately necessary maintenance work on the structure – but it was assessed as being the cheaper plan over the course of a 30-year period, because it removed the requirement to maintain the bridge indefinitely.

In light of the gas main complication and the increased construction bill, however, demolition is no longer considered to be the most cost-effective option for County Hall.

Instead, the authority will now retain and repair the bridge, while still pursuing the reclassification of the road and realising the savings associated with it. The application for that change in status was lodged in March last year and cabinet members were told before Christmas that the Transport Secretary was still “considering various issues” related to the request.

If it is ultimately approved, the top speed on the route is proposed to be reduced from the 70 miles-per-hour (mph) permitted on motorways to 50mph. The road’s hard shoulders would also be replaced with grass verges.

Although the existing scheme does not include specific new facilities for pedestrians and cyclists, “the project is designed [so] that these can be accommodated should a suitable proposal be brought forwards in the future”, cabinet members were told.

County council leader Phillippa Williamson, who represents the Lancaster Rural North division through which the the A601(M) runs, said at last month’s cabinet meeting that she welcomed the road being “upgraded”, as it formed an important “gateway” to the Silverdale Area of Outstanding Natural Beauty.

The originally-planned work had been due to begin in the summer of 2021, but the detailed design process did not start until then because of delays caused by the pandemic.

A shorter southern section of the motorway, which links the M6 to the B6254 Kellet Road, was downgraded in January 2020 and is now known as the B6601. Prior to that change, the stretch was one of only three motorways in the UK comprising just a single lane in both directions.

The proposed reclassification of the remaining northern section was prompted when an assessment found that the five bridges along its length found that they were in need of significant work to ensure that they could remain in use. Back in 2019, the county council revealed that it could be forced to impose weight restrictions on the route – sending heavy goods vehicles on a 21-mile diversion – or even close it altogether.

Unusually, County Hall is the designated highways authority for the A601(M), whereas most motorways are the responsibility of the government agency National Highways.