About 600 lorries will be allowed to cross the Forth Road Bridge — northbound only — between 11pm and 4am in a trial run starting Thursday night, subject to weather conditions, the Scottish Government said.
Recent storms making it unsafe for workers have slowed down repairs and as a consequence the bridge will not fully reopen to heavy goods vehicles (HGVs) with no restrictions until mid-March.
Normally, up to 7,000 HGVs cross the bridge every day.
In the trial run, a dedicated lorry lane will be operated and traffic signals will release HGVs on to the bridge at a rate of one every 30 seconds.
“The release rate has been calculated by engineers as the optimum rate to maximise the number of vehicles able to cross whilst minimising the impact on the structure,” said the Scottish Government.
“This will initially be a trial and the behaviour of the structure will be monitored throughout the process, the outcome of which will determine whether the number of HGVs being allowed to cross the bridge can be increased.”
HGVs account for 32% of the weight on the bridge despite making up only 9% of its traffic.
The Road Haulage Association (RHA) said it was disappointed that the length of the trial run has yet to be determined.
“Since the closure of this vital crossing on 4 December 2015, the financial impact on the thousands of hauliers who are either based in, or making regular journeys to Scotland has been massive,” said RHA chief executive Richard Burnett.
“The Scottish government must find the funds to compensate those operators who, through no fault of their own, have found themselves out of pocket for several months.”
The RHA estimates that since the bridge was closed to all traffic on December 4, the cost to the haulage industry amounts to more than £37 million.
“For the majority of hauliers, each additional cost incurred has to absorbed. Operating margins are already tight and every penny counts.
“Fuel already represents a third of a haulier’s costs. An extra, unplanned, fuel bill of £30 per round trip as a result of diversions, together with a higher wage bill as a result of extended journey times will inevitably mean disaster for many of the smaller hauliers that rely on the quick access the bridge provides.”
Transport minister Derek Mackay said: “90 per cent of traffic returned to the Forth Road Bridge in December and while we recognise that around 600 HGVs crossing the bridge each night does not get us to 100 per cent, it is a step in the right direction – with full reopening expected in mid-March …
“We will not take any decision which could risk damaging the bridge or compromising safety, so we have taken the decision to push back the reopening of the bridge to HGVs to allow time for phase two of the repair work to be complete, with additional time added as contingency due to the effects of the weather.”
Chartered engineer and Amey’s account director for the Forth Road Bridge, Mark Arndt, said: “During the recent storms, the bridge has been closed to traffic, at times, because wind speeds have been so high and it wouldn’t be safe to have people out working in those conditions.
“Our teams are working flat out to complete the work necessary to fully reopen the bridge but our timetable is highly dependent on the weather and our priority has to be on safety.”