Wind weather procedures with Forth bridges: EIR release

Information requested

1· With respect to the two bridges across the Forth (Forth Road Bridge and the Queensferry Crossing) please advise us what kind of windy weather has to occur for the bridges to be closed (whether prevailing wind speed, maximum gust speed or any other information that informs the decision);

2· What are the rules for closure pertaining to cars and vans, coaches and high-sided vehicles (if not already provided);

3· How are those policies created? That is, on what data and guidance, are rules for closing the road for certain vehicles in certain conditions, based?

4· Please provide, or direct us to, any research material or data that has assisted the relevant authority in determining at what wind speed / wind gust speed the bridges ought to be closed.

Response

As the information you have requested is ‘environmental information’ for the purposes of the Environmental Information (Scotland) Regulations 2004 (EIRs), we are required to deal with your request under those Regulations.  We are applying the exemption at section 39(2) of the Freedom of Information (Scotland) Act 2002 (FOISA), so that we do not also have to deal with your request under FOISA. 

This exemption is subject to the ‘public interest test’.  Therefore, taking account of all the circumstances of this case, we have considered if the public interest in disclosing the information outweighs the public interest in applying the exemption.  We have found that, on balance, the public interest lies in favour of upholding the exemption, because there is no public interest in dealing with the same request under two different regimes.  This is essentially a technical point and has no material effect on the outcome of your request.

I have numbered your request and our response for ease of reference;

1, 2 and 4. All of the information you have requested is available from the Forth Bridge website at the following link; https://www.theforthbridges.org/plan-your-journey/wind-and-weather/

3. These procedures were developed independently by the Forth Road Bridge Joint Board and its successor FETA on the basis of their experience at the Forth Road Bridge since it opened in 1964. They take into account the susceptibility of each class of vehicle to wind in the specific conditions experienced at Forth Road Bridge (FRB). This experience at FRB has helped inform procedures on other bridges, rather than data or research from elsewhere being applied to FRB. The last change in these procedures was implemented in 2018 when the Forth Road Bridge reopened as a public transport corridor. Current procedures reflect the fact that fewer classes of vehicle are now permitted to use the bridge, and the wind speed threshold for complete closure has been reduced from 80mph to 65mph for added safety, now that the wind-shielded Queensferry Crossing is available to carry single decker buses safely in winds up to 90mph.

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