From Warminster And District Archive magazine, No.4, May 1990:
Bugley Barton Accommodation Underpass
This structure provides a bridleway and farm accommodation track [Pound Lane] under the Bypass. The width of the track through this structure is 5.5 metres and it has a height of 4.75 metres to provide clearance for farm vehicles. The structure consists of a reinforced concrete box having equal thickness floor, walls and roof of 600mm. The ends have reinforced concrete splayed wing walls integral with the main box structure. The structure has partial construction joints midway along its length and at each wing wall extension. In each joint the steel reinforcement is continuous, the concrete is keyed and the joint sealed from water ingress by an external plastic waterstop and a sealant on the inside. Aluminium parapets are provided behind safety fences as a further precaution.