We present a hybrid system combining immersive and non-immersive technology for traffic engineering experts in the cooperative process of construction site planning and decision-making. We exploit a four-sided CAVE setup, which allows a 360° view of the actual real-world location, while an interactive tabletop positioned in the center of the CAVE provides a map-based 2D planning view. By selecting different locations on the digital map, the 360° environment changes with respect to the selected spot. The tabletop can display more detailed data, e. g., traffic flow and traffic light programs. In the described setup group decisions can be made more effectively compared to current workplace situations. In preliminary focus group discussions, we received positive feedback and plan to expand the system's features in the future.