5. For the purposes of this Part of this Schedule an engine shall be regarded as running at a fast idling speed if—
(a)the vehicle is of a description specified in the Annex to the emissions publication and the engine is running at a rotational speed between the minimum and maximum limits shown against that description of vehicle in columns 3(e) and (f) respectively of that Annex; or
(b)the vehicle is not of such a description and the engine is running at a rotational speedbetween 2,500 and 3,000 revolutions per minute.