The Forth Estuary Transport Authority has laid out the case for the construction of a new multi-modal crossing to supplement the existing Forth Road Bridge. FETA claims the future for the crossing is ‘increasingly bleak’, and a new bridge is the only way to relieve congestion. A report has been produced in response to a request for comments from the Scottish Parliament’s public petitions committee, currently considering petitions for and against a new crossing. This follows the Scottish Executive cabinet’s decision-in-principle to build a new Forth crossing (Surveyor, 2 March). The MSPs were told there were three compelling reasons for building a new crossing: uncertainty over the lifespan of the existing bridge, which may have to be closed regularly in future to ensure safety; the traffic disruption caused by ever-increasing maintenance requirements; and the continuing rise in demand for cross-Forth transport capacity. FETA’s report states that the Forth Road Bridge’s original design load was 2,880t but, due to the rise in the weight and numbers of heavy vehicles using it, in 1986 recommended the assessment load was raised to 5,935t. However, on a typical day, the bridge now carries 180,000t, 50% of which is HGVs, compared with only 6% of traffic nationally. HGVs cause by far the most damage – leading to some calls for them to be banned from using the bridge – something FETA has ruled out as ‘unworkable’. On the issue of the structure’s lifespan, consultant Faber Mansell, commissioned by FETA and the Scottish Executive, has agreed the loss of strength in the cables is 8% and, if the corrosion cannot be halted, restrictions may have to be introduced as early as 2013 – 12 months before the earliest date a new crossing could open. However, their assessment assumes the worst-affected section of cable has already been uncovered. With only 4% of the total length having been inspected, it is possible worse effected sections exist. To increase confidence, the worst section has been uncovered and FETA has started installing an acoustic-monitoring system to detect new breaks among the 11,618 individual wires that make up the main cables. This could reveal worse corrosion in sections and, even in a best-case scenario, the outlook will not improve, as the cable is only as strong as its weakest section. FETA general manager and bridge master, Alastair Andrew, said: ‘Without an alternative crossing, the outlook for cross-Forth travellers is increasingly bleak. ‘What’s more, uncertainties over the lifespan of the bridge’s main cables mean, if we wait to see if remedial work is successful, there may not be time to build a crossing before restrictions have to be introduced or the bridge has to close. ‘A new multi-modal crossing is the only long-term solution,’ he said.