(d) The height of the centre of any such lens from the surface of the road in the immediate vicinity shall not exceed 1.2 metres.
(e) There shall be displayed in association with that lens a device having an area of not less than 50 square centimetres and lined with amber reflectors of amber reflecting material.
(f) where a lamp is used which shows a steady light, then the luminous intensity of that light shall not be less than 0.5 candela measured within 5 degrees above and below and 10 degrees left and right of the principal axis if the light so shown is emitted from the lamp in only one, two or three direction, and measured within 5 degrees above and below the horizontal plane around the vertical axis of symmetry if the said light is so emitted in every direction.
(g) Where a lamp which shows an intermittent light is used, then that lamp shall be of such a size and type that the rate of flashing shall be not less than 900 flashes a minute and the peak luminous intensity measured in accordance with the last preceding sub-paragraph not less than 1 candela; except that where such a lamp is erected within 50 metres of a street lamp lit by electricity on a road subject to a speed limit or 40 miles per hour or less, that lamp may, as an alternative to the size and type last mentioned, be of such a size and type that the said rate shall be not less than 120 nor more than 150 flashes per minute and the said intensity so measured shall be not less than 1.5 candela.
