According to an independent study conducted by Dr Roelof Botha, if motorists productively use at least 15% of the time they save as a result of the improved roads, for every R1 they pay for the tolls, about R8.84 will accrue to them.

Botha, an academic at the University of Pretoria's Gordon Institute of Business Science, described the tolled freeways as a "flagship and unmitigated success".

Releasing the results of his research in Sandton, Johannesburg, yesterday Botha said improved freeways mean massive economic benefits for motorists, companies, the province and South Africa.

Contrary to popular belief by civil society, the Automobile Association, opposition parties and labour unions that the electronic tolls will add an extra financial burden on the poor, Botha's study found:

• The highest-income earners in the province will be responsible for more than 94% of the total toll fees that will be paid.

Combined with the second-highest income earners, the share will rise to more than 99%.

Botha said "together with government's decision to exempt public transport operators from e-tolling, this translates into a progressive nature of user charges, which is compatible with the government's policy objective of poverty alleviation";

• The e-tolling funding model has significant advantages by guaranteeing resources to fund road construction without the delays inherent in having to seek recourse to taxation revenue; and

• Capital investments in the multi-lane free-flow tolled roads has led to a significant reduction in congestion levels on Johannesburg's freeways.

Speaking at a Johannesburg Rotary Club yesterday, DA spokesman in Gauteng, Refiloe Nt'sekhe, said she was not opposed to improving road infrastructure, but that a fuel tax was a better funding model.

Other economists have argued that a petrol tax would have been easier and a lot cheaper.

Not so, said Botha. "If you contrast this to what the food prices will be if petrol prices were hiked, the inflationary pressures will be massive."

Transport Minister S'bu Ndebele put the tolls, which were due to go into effect later this month, on ice, saying there should be more consultation.