Drivers are being forced to pay more than they should for parking due to parking machines not issuing change.
It has been revealed that councils in the east of England are pocketing thousands of pounds, as motorists in the east alone paid more than half a million pounds extra in 2015.
The data, obtained through a Freedom of Information request, showed that almost half of the councils contacted did not reveal a figure, with 21 claiming that they were unable to provide data. Three others said they did not use the pay and display machines.
Between the councils in the East of England, the 26 local authorities that responded to the BBC's request, for information gained more than £550,000 from the overpayments.
The Borough of King's Lynn and West Norfolk pocketed the most from the payment machines, earning £69,629. Not far behind them was Peterborough City Council, which received £66,774.
A spokesman for Peterborough City Council defended the city, mentioning that alternative payment methods are available at all of its car parks. They added: "Pay and display machines that give change are significantly more expensive to purchase and maintain.
"The use of them would mean higher parking tariffs, and so the council has been able to keep tariffs low and competitive compared to other parking operators in the city."
However, the high figure obtained from Peterborough City Council did not include overpayments from two of its car parks. The council also stated that it had been able to keep parking tariffs low by using ticket machines that do not give change, which are cheaper to purchase and maintain than using ones that do.
A representative of RAC said that many motorists would feel as though they are being unfairly charged. They stated: "Half a million pounds might be small change to councils, but to hard-pressed drivers, every penny counts. Many will think they are being made to pay a penalty for doing the right thing and buying a ticket."
Several councils use a "linear tariff" system that gives motorists extra hours for any additional money they pay into the machines.
Cambridge City Council and Maldon District Council, who adopt this method, say that it is fairer to customers.
According to the figures, Cambridge City Council received just £216 in overpayments, while Maldon District Council received none at all.
As councillors are preparing to convert to online and telephone payment systems, pay and display machines could slowly filter out.
There has also been requests for councils to have a system where drivers pay for parking when they leave, which can reduce the risk of them being overcharged.