Traditional urban planning frequently overlooks Children’s Independent Mobility (CIM) – the developmental stage where children begin to navigate their environment without adult supervision. Current educational methods often fail to bridge the ‘knowledge-behaviour gap’ which represents the disconnect between knowing traffic safety rules and applying them in real-world situations. To address this, this study presents a site-specific geogame using a Minecraft digital twin of two school neighbourhoods in Utrecht, Netherlands. Both the game environment and the engagement process were co-designed with traffic-focused local authorities to ensure relevance to real issues. Primary school children navigated the virtual environment and responded to embedded spatial questionnaires regarding traffic safety rules around their schools. The results demonstrate that this approach shifts children’s roles from passive learners to active ‘citizen-experts’. Analysis of in-game movement and chat logs revealed specific spatial insights actionable for planners, including the identification of perceived danger zones and preferred shortcuts. The study concludes that geogames may offer a scalable method to capture children’s situated spatial knowledge and effectively integrate their perspectives into the urban design process.