Pressed by climate emergency, rising population and congestion, EU cities are developing new solutions for sustainable urban mobility. For decades, the EU Commission has supported these initiatives, e.g. by setting mobility goals, regulating public procurement and air quality, establishing networks and funding. Yet, EU cities are still clogged with traffic, pollution and noise. The paper aims at explaining the reasons for this failure, the related challenges of multi-level coordination and advances proposals for reform. It does so by adopting a multi-disciplinary approach (law and sustainability governance) and combining it with an empirical qualitative research incorporating findings collected 1) through document analysis of EU and local policies and 2) semi-structured interviews with institutional experts at EU level and in two Dutch cities. This analysis delivers an evidence-based evaluation of EU policies’ impact to realise sustainable urban mobility.