Parking enforcement in Devon has been losing about £600,000 a year for the past four years, according to a report.
The county council has now ordered an independent review of the service which was taken over from police in 2008.
More than 50 full-time parking wardens, or civil parking enforcement officers, hand out about 50,000 tickets every year in Devon.
Liberal Democrat councillor Gordon Hook called the losses "appalling" and "unsustainable".