Drivers who do not take sufficient care to look at a vehicle could find their employers end up paying for vehicle damage that they did not cause, either because it was there when the vehicle was delivered or happened after it was handed over.
Arval PHH is now urging fleet decision-makers to warn drivers about the growing problem of unreported damage.
Problems arise primarily when rental vehicles are delivered and collected. Cars can often be delivered to private homes hours before the rental period was scheduled to start so the hirer is unavailable to inspect for damage.
As a result, damage caused by a previous hirer may be missed on the delivery condition report but picked up at the end of the current rental.
This could lead to a situation when the current hirer is blamed for damage that he or she did not cause.
Arval PHH adds that as many companies charge their employees the excess in the event of an accident, drivers may also be reluctant to notify the supplier, hoping that the damage will not be noticed.
Mark Graham, product development manager at Arval PHH's rental division, said: 'Rental companies are having to introduce new methods to deal with unreported damage, which is causing some of the larger suppliers to write off millions of pounds every year.
'These initiatives have included not collecting the vehicle until the hirer is available to sign for it, or perhaps using digital cameras to log damage with the driver present.
'Daily rental remains a vital part of many fleet policies. However, by getting their drivers to take a bit more care companies could be protecting themselves from unnecessary vehicle repair costs and ensuring that they stay on good terms with their rental suppliers.'