WeCount was designed to empower citizens in five case studies across Europe to take a leading role in the production of data, evidence, knowledge and solutions for local sustainable mobility. This practice insight aims to explore the suitability and value of citizen science to address sustainable mobility and sustainable transport issues. The evaluation showed that WeCount was able to reach and sustain engagement with broad demographics in society and highlighted the importance of co-design in making citizen science enjoyable and empowering. Statistical significance was found: the more a citizen enjoyed their time, the more likely they were to state they would continue working with the data beyond the project. Moreover, WeCount citizens reported that participation led to action and/or changes in behaviours. While the numbers are modest (24 individual actions by around 10% of participants), this is an important, measurable outcome.