Johannesburg - The transport department on Thursday refuted the DA's claims that it is misleading motorists about e-toll tariffs.
"The system we have in place has so many capabilities that go beyond collection," spokesperson Tiyani Rikhotso said.
"It assists with travel demand management survey. Therefore, we have an accurate idea of how many cars pass a gantry."
Earlier, Democratic Alliance Gauteng premier candidate Mmusi Maimane said it was hard to believe that more than 80% of users with an e-tag would pay a maximum of R100 a month.
The party said a driver travelling from Daveyton to Johannesburg would pass through at least five gantries on a return trip, at an approximate cost of R13.92 a day. This amounted to R69.60 in a five-day week, and R278.40 in a month of 20 working days.
The DA said that travelling between Alexandra and Centurion, a user would pass through at least six gantries at an approximate cost of R17.31 a day, R86.55 a week, and R346.20 a month.
From Soweto to Midrand, a driver would pass through at least 11 gantries on a return trip, at an approximate cost of R29.64 a day, and would reach the threshold of R400 a month.
For a commute between Tembisa and Germiston, a motorist would pass through at least four gantries on a return trip, at an approximate cost of R14.40 a day, R72 a week, and R288 a month.
Rikhotso said from the information collected, the department could track the frequency at which a motorist used a stretch of road.
"From that, we are able to sample and calculate how much they use. There is nothing more accurate than that."
He moved to assure motorists that no matter how many trips they made in between the gantries, they would not pay anything above the set R450 cap. Even if a car made trips amounting to R3 000 a month, only the set amount of R450 would be payable.
He challenged the party to provide evidence to support its claims.
"We will welcome anything that prove that our findings are incorrect," he said.