As macroscopic travel demand models are widespread among regional modelers, it is crucial to develop extensions for new mobility services such as ride-sharing services to assess their effects on the transport system. In a feasible approach that was introduced with previous research, origin-destination network-based paths are transformed to a series of crossed traffic analysis zones (TAZs). These series are compared to find overlapping trajectories to derive ride-sharing potential. However, in national transport models the TAZ sizes are larger than in regional models, which can lead to unrealistically high matching rates because of imprecise path trajectories. This paper presents a modified approach for implementation in the German national transport model, DEMO. The main adjustment is to use population centers as pick-up locations instead of TAZs. Each TAZ includes multiple points. This way, the trajectories of paths can be better differentiated. Another advantage of this method is that intrazonal trips can be distributed between the centers and thus be included in the algorithm. With the successful implementation in DEMO, the effects of new mobility tools in German cities can be evaluated within the same model.