Queensferry Crossing: Automated barrier system trial cuts time to implement Forth Road Bridge diversion

The barriers are the first of their kind to be used in the UK and remove the need for most of the manual work previously required to divert traffic.

At the touch of a button the eight barriers move themselves across the carriageway to redirect the M90 motorway directly onto the neighbouring Forth Road Bridge.

In the first full trial deployment of the new automated system, which took place on Sunday, the M90 traffic was running over the Forth Road Bridge just 38 minutes after all traffic on the approaches to the Queensferry Crossing had been stopped. Previously, it took up to six hours to manually erect the traffic management required for such a diversion.

There is scope to further reduce the timescale with works planned in 2024 to install ‘intelligent road studs’ that will light up to guide traffic onto the diversion route removing most of the requirement to lay out cones. Additional electronic components will also become available next year that will allow the system to be fully automated, with the barriers opening and closing simultaneously rather than being operated individually as at present.

Following the trial another area was identified where improvements could still be made. It took over 20 minutes for traffic on the southbound carriageway of the M90 to comply with red X signs on the overhead gantries, meaning that the first drivers to stop on other approaches had to wait almost an hour in total before the route onto the Forth Road Bridge was open. On the northbound approach where there was a police presence it only took two minutes for traffic to comply.

Chris Tracey, BEAR Scotland’s south east unit bridges manager, said: “From a technical perspective the trial of the new barrier system was a success. This is new technology for the UK and it is being deployed on a larger and more complex sccale than in other locations where it has been used before. The machinery worked as designed and dramatically reduced the time it takes to open the diversion route over the Forth Road Bridge.

“Crucially, it is now faster to redirect M90 traffic onto the Forth Road Bridge than it is to divert via the Kincardine Bridge, so this will be the default process from now on if the Queensferry Crossing has to close for any reason.

"There are limits to how quickly the diversion can be opened, as traffic management must still be put in place to close slip roads at Queensferry and Ferrytoll and traffic already on the Queensferry Crossing must be given time to clear the bridge, however our aim is to speed up the overall process as much as possible and we learned a lot from this trial that will help us to do this.

"One of the biggest areas for improvements was in the time it took for traffic to comply with red X signs on the overhead gantries. These instructions to stop are mandatory and we’ll provide any assistance we can to help Police Scotland enforce them.”