Queensferry Crossing falling ice: Automated barriers test sabotaged by idiot drivers – Alastair Dalton
The last thing anyone thought might close the Queenferry Crossing was falling ice.
The £1.35 billion bridge has been a big success in every other way, with its windshielding and hard shoulders dramatically reducing the number of times restrictions have had to be imposed, and amount of disruption caused from breakdowns and crashes, compared to the Forth Road Bridge which it replaced six years ago.
But an unexpected headache came when it was discovered that a specific combination of weather conditions caused ice to form on the structure’s support cables before falling as “ice bombs” onto the carriageways below, in some cases damaging vehicles.
Since The Scotsman was first to report on the phenomenon in 2019, the mystery has still to be solved, despite extensive tests including at the Jules Verne climatic wind tunnel in Nantes.
A possible explanation has been suggested by the fact there have been no further incidents since the cables were cleaned over the last two years.
Meantime, bridge operator BEAR Scotland has focused on minimising traffic disruption should it happen again.
Originally, it took hours to switch vehicles onto the Forth Road Bridge, with barriers and cones having to be moved manually.
However, in a series of recent overnight tests, new automated barriers have been successfully trialled.
The Dutch-made barriers move themselves across the carriageways, reducing the switchover time from around six hours to 38 minutes. BEAR said that could potentially be reduced further with road studs that light up to guide traffic onto the diversion route.
However, I was astounded to hear that the operation early on Sunday November 5 could have been completed one third quicker if southbound motorists hadn’t continued to drive through red X signs on the overhead gantries that warned of the lane closures for an extraordinary 20 minutes after they were switched on.
That delayed the first northbound drivers – who perhaps stopped more promptly by the presence of a police car – by nearly an hour. If that should happens when ice is falling, it sounds like a recipe for damaged vehicles and idiots cancelling out the new barriers’ time saving.
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