Car rental companies have agreed to review how they treat customers following a joint action from the European Commission and national enforcement authorities.
Avis-Budget, Enterprise, Europcar, Hertz and Sixt will ensure more clarity on insurance policies and tank refuelling options, fairness when handling damages and more price transparency.
European Consumer Centres had seen complaints related to car rentals increase sharply in the last two years.
V-›ra Jourov, EU commissioner for Justice, Consumers and Gender Equality said: "Booking a car online, renting it in one country and returning it in another is very simple today.
"Unfortunately, car rental terms and conditions are sometimes too vague or lack clarity. Consumers are too often left with unplanned extra costs.
"Five major car rental companies have now pledged to improve their information policies and make their terms and conditions fairer for consumers. I welcome their commitment and the excellent work done by the national consumer authorities in ensuring a better deal for European consumers."
The proposals are gradually being implemented by the car rental firms and should be completed by the end of 2015.
