> It seems pretty clear that whatever the cause, it was an extremely rare incident. It may be rare in the lifetime of the bridge, but if there is a variable wh

> It seems pretty clear that whatever the cause, it was an extremely rare incident. It may be rare in the lifetime of the bridge, but if there is a variable which has change (or is moving) then that isn't so important a consideration. For example, if container ships have recently become much larger in relation to the design requirements in place at the time of the bridge's construction.