Across Europe, road safety experts increasingly agree on one fundamental point: lasting reductions in road deaths and serious injuries require enriching our proven traditional road safety effort by understanding how road users and institutions think and decide, i.e. their traffic safety culture. We all have an intuitive perception that road users are influenced by their culture. Personal experiences of driving in another country come to mind – or how foreign road users act on our familiar routes. In fact, we are all subject to multiple cultures. And while a country’s culture explains some of its behaviour – due to shared jurisdictions, history and experience – the decisions of road users may equally be shaped by additional cultural layers, such as shared beliefs within a family or among friends about how we are supposed to act. To change road users’ culture requires a shared definition of what Traffic Safety Culture is and a common understanding among road safety researchers and professionals. Once there is consensus, we are one step closer to measuring and growing Traffic Safety Culture effectively. The Safe System approach emphasises the principle of shared responsibility and the crucial role of organisations for safe mobility. Yet, institutional silos persist and one-off safety interventions are widespread. Where safety culture is weak, safety measures may be perceived as additional burden – costly and restrictive. Where culture is strong, safety becomes a core organisational value, influencing design standards, enforcement practices, training, and daily operational choices amongst other things. A strong Traffic Safety Culture provides a common purpose, enabling alignment of priorities and making collective decisions focused on reducing harm. Systems thinking also means thinking outside the (safety) box, so, for instance, environmental sustainability become a road safety ally. Strengthening culture does not have to be an abstract ambition. The TRUST project has taken on the challenge and is working towards establishing a common language and definition, measurement tools and interventions by 2028. By Susanne Kaiser and Klaus Machata