Many motorists have paid unnecessary fines because councils don't follow the proper complaints procedure.
A report by the Local Government Ombudsman for England says that councils are not making it clear that drivers can appeal against fines, and in some cases dismiss complaints without properly considering them.
The report said: "Our work investigating these cases suggests that sometimes motorists may be paying more than they need to because they have not been given the correct advice about how to challenge their tickets."
Officials found that some parking tickets were issued without any information about how to appeal. In some cases, the only phone number on the ticket was for paying a fine rather than discussing it.
The report notes that although this is not illegal, "it may discourage people from contacting their council with valid inquiries," and potentially went against official guidance that tickets must be issued "objectively and without regard to any financial interest."
Further guidance for councils says that all fine complaints must be considered, with the reason for a rejected complaint explained. However, it said: "All too often, we see cases where a council simply rejects the motorist's explanation of why they incurred the penalty charge notice, without giving reasons; or fails to consider them properly at all."
The ombudsman Michael King said: "If motorists genuinely feel a parking ticket they've received is unfair, they should be aware that they have a legal right to appeal to an independent parking tribunal and the council should not reject valid concerns out of hand."