container enclosing apparatus for the illumination of that sign, shall be coloured—
(a) black, if the sign is mounted on the same post as that on which light signals prescribed by Regulation 31(2) of the Regulations or those signals as varied by Regulation 32 thereof, or prescribed by Regulation 33 of the Regulations are mounted, and
(b) grey in any other case except that information about sites for placing the sign may be indicated on the back of the sign in white characters not exceeding 15 millimetres in height.
38. The traffic signs shown in diagrams 806, 806.1, 807 and 808.1 may only be placed on or near a road if every road contained within the controlled parking zone indicated by the said signs so shown has been marked with a road marking of a kind shown in one of the diagrams 1016.1 to 1021 appropriate to the nature of the restriction in force except in so far as the parking places for vehicles have been designated and provided on that road.
In this paragraph the expression "controlled parking zone" has the same meaning as in paragraph 28 of these Directions.
39. The light signals prescribed by Regulations 31(3) and 38 of the Regulations and the light signals shown in diagrams 5002 and 5004 may be displayed only on or near a motorway.
40. The light signals prescribed by Regulation 31(3) of the Regulations shall not be displayed over or in relation to a traffic lane (as defined by Regulation 36(1) of the Regulations) at the same time as any sign shown in any of the diagrams 6001 to 6005 is also being displayed over or in relation to that same traffic lane and at the same place on that lane.
41. The traffic signs shown in diagrams 6002 and 6004 may be displayed only over a traffic lane as so defined and the signs shown in diagrams 6006, 6007 and 6008 may be displayed only at the side of the carriageway to which the indications given by those signs relate.
42. (1) Without prejudice to the provisions of paragraph 34 of these Directions, this paragraph applies to all traffic signs which are not continuously in use as such signs over a period of 24 hours and are capable of being brought into, and taken out of use for the time being as such signs by the operation of any electrical or other equipment apt for the purpose of bringing those signs into or taking them out of use.
(2) The type of the said electrical or other equipment by which the traffic signs to which this paragraph applies are brought into, and taken out of use as such signs and the type of any other apparatus (including the content of all sequences of stored instruction whether executable by it or not) used to secure that the said traffic signs comply with the provisions of the Regulations shall first have been approved in writing by or on behalf of the Secretary of State before the said traffic signs are placed on or near any road.
43. At least two road markings of the kind shown in diagram 1014 and so spaced apart that the one follows in line in front of the other shall be placed on any length of carriageway which extends backwards for a distance of not less than 30 metres measured along a line parallel to the centre line of the carriageway from the commencement of any continuous line marked on the carriageway as a part of the marking shown in diagram 1013.1, such commencement being viewed in the direction of travel of a vehicle driven so as to have and keep that continuous line on the right hand or off side thereof in accordance with Regulation 23(2)(b) of the Regulations.
