Restriction on the construction of overrun areas

5.  No overrun area shall be constructed in a road unless it complies with one of the sets of specifications in the Schedule to these Regulations, so, however, that a measurement shall be deemed to comply if it is—

(a) in the case of a vertical measurement, no more than 5 per cent or 1 millimetre, whichever is the greater;

(b) in the case of an angular measurement, no more than 5 per cent or 1 degree, whichever is the greater;

more than the corresponding measurement shown in the specification.