Appendix 3 Footnotes

1 la-hr represents one lane open to traffic for one hour [(0.8% + 0.6%) / 2 =0.7% full availability = 0.007 X 17520 = 123] Where 0.8% is the northbound carriageway availability; 0.6 % is the southbound carriageway availability and 17250 is based on each carriageway of the FRB having two traffic lanes and so the maximum lane availability in each direction crossing the Forth is 2 x 8760hours per year = 17520 la-hrs.
(0.75 x 183.1) x 1 x (21/60) + (0.25 x 183.1) x 2 x (21/60) = 48.1 + 32.0 = 80.1 lane-hours/year (round up to 80 lane-hours/year.)