The sustainable development of modern cities requires both spatial planning and properly designed and managed transportation systems. Without proper attention to these aspects, cities become too car-dependent, experience air pollution, and have a lower quality of life. According to data from the Central Register of Vehicles and Drivers, Rzeszow ranks third in Poland in terms of the number of cars, with 865 vehicles per 1,000 residents. This indicates that the city faces serious challenges related to sustainable development stemming from the dominance of car transport. The authors investigated the effects of implementing key guidelines of the SUMP strategy at the programming stage of an architectural competition. To achieve this, they conducted multiple urban planning and transport analyses of vehicular traffic, public transport accessibility, and functional surroundings. As part of the transport analyses, microsimulation models were developed to provide detailed insights into traffic flow dynamics and to assess the potential impact of the proposed solutions. Studies have resulted in the development of “Assumptions for Shaping the Traffic Service of the Planned Investment”, taking into account the SUMP strategy as much as possible: promoting walkability, reducing reliance on private cars, and creating accessible, inclusive public spaces. The SUMP directives have also influenced the functional program of the planned cultural complex, which has been considerably diversified as a result.