From Roader's Digest: The SABRE Wiki
Daviot Bridge carries the A9 across the River Nairn to the south of Inverness. The modern bridge is a single span dual-carriageway structure supported by girders. However, immediately downstream the old bridge still stands. This carried the A9 before the new route was constructed, and saw the road turn sharply across the bridge to double back on the opposite side of the valley along what is now the B9154.
Strangely, when the A9 was dualled here, a new junction for the B9154 was constructed on the south side of the new bridge, rendering the old bridge defunct. It is still standing and surfaced, but runs into the banking for the new A9 at the western end. Its only remaining purpose appears to be to provide fishermen with access to the riverbank!
The old bridge is a single span stone arch, built on a slight curve as it crosses the river. Whilst its date is not currently certain, it appears to be 19th century. A more modern concrete/steel rail parapet has been added at some point, although the northern one has since disappeared once more!