"The Court of Justice of the European Union's (CJEU) decision of 14 May 2019 in Case C-55/18, CCOO represents an important milestone in the Court's case law on working time. This decision raises specific questions about the adequacy of national laws and offers interpreters an opportunity to reflect on certain challenges related to the measurement of working time. The aim of this contribution is to highlight the significance of the CJEU's decision and its implications for national legislative frameworks. After providing a brief analysis of the ruling, the article focuses on the following aspects: how to ensure that working time is accurately recorded for the purpose of enforcing the Working Time Directive, and in the light of lessons learnt from some national experiences (section 2); the usefulness of the obligation to measure working time within the context of the burden of proof in individual disputes (section 3); under which conditions Member States can take advantage of the leeway provided by the Court in the implementation of the principle of compulsory monitoring of working time, especially for activities for which working time is not measured and/or can be (pre)determined by the workers themselves (section 4); and the challenges posed by teleworking and agile work (section 5)."

Support: Digital