25: In Search of the Value of Time: From South Africa to India

The route choice behaviour of potential toll route users and their perceived values of time (VOTs), which determine their choice of route, are critical in modelling the toll income stream of a proposed toll road. This is also fundamental in assessing the financial risks of the financiers of the toll road investment. Internationally the most acceptable approach is to use individual choice or discrete choice models calibrated on the potential users' actual route choice behaviour (revealed preference – RP) as well their intended behaviour (stated preference – SP). The VOT is subsequently used in network transport models such as EMME/2 and SATURN so that these models reflect the correct distribution of trips amongst alternative routes for each Origin-Destination pair of the trip matrix. VOTs are therefore critical parameters in the trip assignment process and it is important that VOTs are estimated accurately.