The Traffic Signs Regulations and General Directions 2002

Signs attached to vehicles

14.—(1) Any sign attached to a vehicle of the description specified in column (2) of an item in the Table and in the position on that vehicle specified in column (3) of the item, when the vehicle is on a road which is subject to a maximum speed limit specified in column (4) of that item, shall be of the size, colour and type shown in a diagram specified in column (5).

Table

(1)	(2)	(3)	(4)	(5)
Item	Description of vehicle	Position on vehicle	Maximum speed limit	Diagrams
1.	Road maintenance vehicle	On the front	30 mph or under	610, 7001, 7001.1
2.	Road maintenance vehicle	On the rear	30 mph or under	610, 7001, 7001.1, 7402, 7403, 7404
3.	Road maintenance vehicle	On the rear	More than 30 mph	7402, 7403, 7404
4.	Road maintenance vehicle immediately ahead of a vehicle displaying the sign shown in diagram 7403	On the rear	More than 30 mph	610, 7402, 7403, 7404
5.	Police vehicle	On the front or the rear	70 mph or under	829.1, 829.2, 829.3, 829.4

(2) The operating requirements for the lamps that form part of the signs shown in diagrams 7402 and 7403 are that—

(a) the lamps shall be illuminated only when the signs are being used in accordance with the Table; and

(b) each lamp shall show an intermittent amber light at a rate of flashing of not less than 60 nor more than 90 flashes per minute, and in such a manner that the lights of one horizontal pair are always shown when the lights of the other horizontal pair are not shown.

(3) A sign attached to the rear of a vehicle used to escort traffic through road works, and indicating that the vehicle should not be overtaken, shall be of the size, colour and type shown in diagram 7029.