Thousands of motorists issued with parking tickets are victims of badly paid, poorly trained wardens who lack discretion, according to a University of Birmingham study.
The report calls for local authorities to invest the same attention to quality in parking enforcement as they do in other areas.
Customer service and public-accountability should be at the heart of parking enforcement regimes rather than the number of tickets issued, the report, funded by parking firm NCP, adds.
A team from the university's Institute of Local Government Studies carried out the six-month research project to investigate the very best practices in council-run parking enforcement.
Six local authorities were identified and nominated by peers as demonstrating highquality practices: Winchester, Hammersmith & Fulham, Manchester, Cambridge, Weymouth & Portland, and Sunderland.
Professor John Raine, lead investigator on the study, said: "In our analysis, high quality in parking enforcement is achieved when there is both good compliance with the parking regulations and also public support.
"Too often councils have been pursuing rigorous enforcement without that vital ingredient of public support.
"There is much more that can be done to improve communication and build public confidence in the purposes and integrity of the process.
" The six good- practice councils provide many valuable lessons for other local authorities and contractors, and we hope that the research hastens the pace of change for the better."
Last year, Birmingham had the second highest amount of fines and charges recovered from motorists outside London. The city's motorists were hit with a total bill for £17.8 million. Croydon was highest with £21.2 million.