Paper presented at the 24th Annual Southern African Transport Conference 11 - 13 July 2005 "Transport challenges for 2010", CSIR International Convention Centre, Pretoria, South Africa.
Paper presented at the 20th Annual South African Transport Conference 16 - 20 July 2001 "Meeting the transport challenges in Southern Africa", CSIR International Convention Centre, Pretoria, South Africa.
Paper presented at the 20th Annual South African Transport Conference 16 - 20 July 2001 "Meeting the transport challenges in Southern Africa", CSIR International Convention Centre, Pretoria, South Africa.
