The Road Works (Qualifications of Supervisors and Operatives) (Scotland) Regulations 1992
These Regulations prescribe the qualifications needed for supervisors (regulation 3) and trained operatives (regulation 4), one of each of whom is required by section 126(1) and (2) of the New Roads and Street Works Act 1991 (subject to exceptions) to supervise or be on site at all times when an undertaker executes road works involving, in the case of both supervisors and trained operatives, breaking up the road, or any sewer, drain, or tunnel under it, or tunnelling or boring under the road and, in the case of trained operatives, opening the road.