When you want to get a car for rent, you should sign a contract. This signing of a contract is mandatory, without which you will not get the rental car (hyrbil) from the carrental (biluthyrning). This contract will have all the terms and conditions which the company expects you to follow. You should make sure that you have read all these terms and conditions before signing the contact. The contract spells out the liabilities that you will face in certain situations. By signing the contract you agree to all the terms and conditions that, the company has put forward.
You will be at a liability if you violate any rules and regulations of the rent a car (hyra bil) contract. The contract will also mention that the driver should be above a certain age limit. This is usually for the luxury cars. You should also note that the contracts for the luxury cars will be different from the contracts for normal cars.