Sustainability has been a fundamental principle of urban planning for the past few decades, and its role and importance will certainly influence many spatial policies in the decades to come. This is especially true for those policies focused on mobility because many cities, including Zagreb, face challenges with inefficient public transport and car traffic congestion. The paper is conceived as a project-based research conducted at the Graduate workshop course at the Study of Architecture and Urbanism at the Faculty of Architecture in Zagreb. The focus of the research is the concept of sustainable mobility tested at the area of Savska street, one of the oldest and most important traffic access routes to Zagreb. As a result of critical review of relevant literature, planning documents and site analysis, a concept of urban transformation is proposed at two levels. The first level refers to the planning scale at the wider area of city district, and the second level is the urban design project of one of selected new public outdoor spaces. The planned city transformation is evaluated by established criteria and indicators divided into general topics of traffic, green space and land use. In conclusion, it was found that the proposed scenario represents a possible model of establishing different aspects of sustainability based on increasing the share of parkland that provides a green infrastructure system, as well as a new network of pedestrian and bicycle routes in a newly planned mixed-use city development area. In such manner, the basic preconditions could be achieved for a more accessible, inclusive and healthier city, as well as the promotion of an integrated public transport system.