Here it is from the book:
http://www.acts.co.za/rt_nrta/index.htmNational Road Traffic Act, 1996
National Road Traffic Regulations, 1999
Chapter X : Rules of the road and matters relating thereto
Part I : Rules of the road
309. Duties relating to motor cycle, motor tricycle or motor quadrucycle
6)
a) Persons, other than traffic officers in the performance of their duties, driving motor cycles on a public road, shall drive in single file except in the course of overtaking another motor cycle, and two or more persons driving motor cycles shall not overtake another vehicle at the same time: Provided that where a public road is divided into traffic lanes, each such lane shall, for the purposes of this paragraph, be regarded as a public road.
EXPLANATION:
A motorcycle may treat each lane as a public road, i.e. may overtake another vehicle on that road. (in that lane