South Australian Numbered Regulations South Australian Numbered Regulations90—Vehicles needing side marker lights
(1) A pair of side marker lights must be fitted towards the rear of the sides of a motor vehicle that is over 7.5 metres long and at least 2.2 metres wide.
(2) A pole-type trailer, and a motor vehicle built to tow a pole-type trailer, with at least 1 cross-bar or bolster must have a side marker light fitted to each side of the back or only cross-bar or bolster.
(3) A pole-type trailer with 2 or more cross-bars or bolsters may also have a side marker light fitted to each side of the front cross-bar or bolster.
(4) At least 2 side marker lights must be fitted to each side of—
(a) a trailer, except a pole-type trailer, that is at least 2.2 metres wide and not over 7.5 metres long; or
(b) a semi-trailer that is not over 7.5 metres long.
(5) At least 3 side marker lights must be fitted to each side of—
(a) a trailer, except a pole-type trailer, that is at least 2.2 metres wide and over 7.5 metres long; or
(b) a semi-trailer that is over 7.5 metres long.