Fleets are being urged to challenge the costs associated with road repairs after an accident.
A claims management company said it has achieved five-figure savings for clients by contesting claims listed in invoices from repair companies.
If Crown property - for example a motorway barrier or a road sign - is damaged, insurers or the person responsible for the damage are presented with a bill from a council, Highways England, Transport for London or a contractor.
Claims Management & Adjusting said it is "wise" to "scruitise the invoice" citing an example where a fleet operator was billed for £46,000 for barrier repairs without realising the length of the replacement barrier needed was published in yards rather feet. The claim was then written off thanks to the contractor being described as "problematic" by Highways England.
The company also claimed it reduced a £56,000 resurfacing bill by using a Freedom of Information Act request to show a larger stretch of road had previously been resurfaced for £750.
"Certain Highways England contractors seem to be acting in an informal environment. The tail appears to be wagging the dog, particularly where contractors have agreements to retain claims under a certain threshold, commonly £10,000," said Paul Swift, managing director of CMA.
"My experience of dealing with hundreds of these below-radar claims, which Highways England acknowledge they do not supervise, has caused me to question whether many of the costs being presented are accurate or appropriate," he continued.
"There is a shocking lack of transparency- and we frequently see cases of serious overcharging."