ING Car Lease is also urging fleets with drivers taking summer holidays abroad to check vehicle documents and paperwork before an international journey.
Drivers taking a company vehicle aboard must have a VE103B document and permission from the leasing company, giving approval for the vehicle to be taken out of the country.
ING recommends that company cars also have a first aid kit, fire extinguisher, spare lamp bulbs and a spare set of keys.
Fleets have also been warned to ensure any drivers suffering with hay fever are aware of the dangers.
If a hay fever sufferer repeatedly sneezes at 70mph, vision can be lost for up to half a mile, according to the Institute of Advanced Motorists (IAM).
Bryan Lunn, chief examiner at the IAM, said: 'There are some simple things a driver can do if they are having a bad hay fever day. Try to get someone else to drive. If not, keep all the windows closed.'