The practice of international transport services is different from that of domestic transport and this is understandable. However, understanding and applying them properly is not an easy task either. The operation of two types of contract, namely CMR and cabotage contracts, is an example of how it is easy to come to the conclusion that the problem is the resolution of disputes arising from them by national courts, which have been shown to often have to resort to the technique of interpretation of the rules in order to resolve the legitimacy of the legal problems that arise on this basis. National courts, which are also European courts, have a great deal of attention over this part of their application. Thanks to this construction of their functioning, national courts deciding on events of mixed national and international character can ask the CJEU for a binding interpretation which, in this respect, will also cover the application of the rules in other European Union Member States. After all, a significant example in this respect is the issue of the different treatment of cabotage operations carried out in connection with the CMR contract. Therefore, unless there are legal problems, the functioning of obligatory agreements in this area will not pose problems. If a problem arises, such as the possibility of carrying out cabotage operations by a third party, but already having a branch in a Member State, it is an issue that must be interpreted by the CJEU, whose role as a court of law in this area gives rise to hopes that economic turnover within the European Union will become uniform over time, and thus also simplify, despite the differences that exist between the different legal systems of its Member States.