may be of such size, colour and type as is specified in the following provisions of this Regulation.
(2) Every such sign placed as aforesaid (hereinafter referred to as a "temporary sign") shall be of a shape which
(2) is rectangular;
(b) is rectangular, but with the corners rounded; or
(c) is rectangular, but with one end pointed.
(3) Every temporary sign shall be of such size as is necessary to accommodate the wording, numerals and arrows or chevrons appropriate to the purpose for which it is placed as aforesaid and any arms, badge, device, words or letters incorporated in the sign in accordance with the provisions of paragraph (6) of this Regulation.
(4) Every letter and numeral incorporated in a temporary sign other than any letter incorporated in the sign in accordance with the provisions of paragraph (6) of this Regulation shall be not less than 14 inches nor more than 10 inches in height, and every arrow so incorporated shall be not less than 10 inches nor more than 20 inches in length except that where an arrow is incorporated in the index part of a sign with a pointed end such arrow shall be not less than 4 inches nor more than 8 inches in length.
(5) Every letter, numeral, arrow or chevron incorporated in a temporary sign shall be
(a) black on a background of white, silver or yellow; or
(b) white or silver on a blue background.
(6) There may be incorporated in or attached to a temporary sign the arms, badge or other device of a highway authority, police authority or the Royal Automobile Club, the Royal Scottish Automobile Club or the Automobile Association or words or letters indicating the highway authority or that the sign is a police sign.
(7) No sign shall by virtue of this Regulation convey to traffic any warning, requirement, restriction or prohibition of a description which can be so conveyed either by a sign shown in a diagram in Part I or Part II of Schedule 1 or by a sign so shown used in combination with or in conjunction with another sign shown in such a diagram.
Flashing beacons
28.—(1) Beacons showing an intermittent amber light for conveying the warning that drivers of vehicles should take special care may be used in combination with or in conjunction with any of the signs specified in the last preceding Regulation or with any of the signs shown in diagrams 562 to 569, subject to the following conditions:
(i) the dimensions of the lenses shall be not less than 5 inches nor more than 8 inches measured in a straight line in any direction;
(ii) the height of the centre of the lenses from the surface of the carriageway in the immediate vicinity shall be not less than 4 feet nor more than 8 feet;
(iii) the rate of flashing shall be not less than 50 flashes per minute and the period between flashes shall not exceed 6/10ths of a second; and
(iv) the structure, if any, on which the beacons are supported shall be coloured black and white in alternate sloping bands.
