Paper presented at the 28th Annual Southern African Transport Conference 6 - 9 July 2009 "Sustainable Transport", CSIR International Convention Centre, Pretoria, South Africa.
Spiralling road construction and maintenance costs combined with the limited funding for the expansion of the road network means that road authorities must justify the need to implement road projects. Traffic transport models are tools that can provide answers regarding the evaluation of alternative road network improvement options including the analysis of the benefits of a project as well as the potential impact on other parts of the road network. A significant project in this regard is the Gauteng Freeway lmprovement Project (GFIP), currently being implemented by the South African National Road Agency Limited (SANRAL). This paper describes noteworthy lessons learned while developing the GFlP transport model with the aim of providing some insight to transport modellers and those who rely on the output from these models what can be expected from them and where the engineer fits into this picture.