No vehicle shall, subject to the provisions of section 79 of this Act and of any regulations made under section 78(5) thereof, show—
(a) a red light to the front, or
(b) any light to the rear, other than a red light or a white light for the purpose of reversing.
Paragraph (b) of subsection (1) above shall not prevent a vehicle from carrying a lamp showing a light to the rear for the purposes of—
(a) the internal illumination of the vehicle, or
(b) (subject to subsection (3) below) illuminating a number plate, taxi meter, or any device for giving signals to overtaking traffic, or
(c) in the case of a public passenger vehicle, illuminating boards, plates or devices indicating the route or destination of the vehicle ;
and the said paragraph (b) shall not prevent a bicycle or tricycle from carrying amber coloured reflectors which are attached to or incorporated in or form part of the pedals of the bicycle or tricycle notwithstanding that any such reflectors show a light to the rear.
Subsection (2)(b) above shall not authorise a vehicle of any class to carry a lamp showing a light to the rear for the purpose of illuminating any device for giving signals to overtaking traffic other than a device of a type required or authorised to be carried on a vehicle of that class by virtue of section 40 of this Act.