## 3 Results
### Underused Resources  
Urban passenger transport is characterized by both temporal and spatial peaks. There is also a certain variance in passenger numbers on different road sections. Between 1979 and 1998, various strategies were introduced to counteract these peaks. More information on these strategies, namely \"short turning\", \"expressing\", and \"deadheading\", can be found in the literature [45; 46; 47]. [PERSON] et al. [48] examined the combination of short turning and deadheading, which made it possible to reduce the movements of empty vehicles and thus reduce operational costs. \begin{table}
\begin{tabular}{c c} \hline \hline
**Code Name** & **Code Groundedness** \\ \hline Cooperation & 38 \\ Public space & 27 \\ Infrastructural barriers & 26 \\ Private spaces & 20 \\ Available space & 18 \\ Micro hub & 18 \\ Scarcity of urban space & 18 \\ Cargo bikes & 14 \\ Location selection & 14 \\ Transitory use & 14 \\ White label & 13 \\ Efficient use of urban space & 12 \\ Last mile distribution & 12 \\ Vacant area (parking) & 12 \\ Areas for parking & 11 \\ Coordination & 11 \\ Mixed usage & 11 \\ Multi-story buildings & 11 \\ Noise emissions & 11 \\ Warehouse & 11 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Code Groundedness with respect to Idle Real Estate. In addition to these strategies to increase vehicle use efficiency in passenger transport, there are also approaches to reduce empty runs in freight transport, such as collaborative pick-up deliveries, collaborative collection, and collaborative cross-docking. [PERSON] et al. [27] find that the application of these collaborative strategies could reduce global operation costs by 28% and global fuel consumption by 26%, leading to a significant decrease in CO2 emissions. While conventional concepts tend to focus on either passenger or freight transport individually, there is untapped potential in combining both types of transportation to maximize the utilization of empty vehicles. [PERSON] and [PERSON] [14] propose a flow-based model for the city of La Rochelle in France, which capitalizes on the available capacity in passenger buses to transport goods alongside passengers. [PERSON] et al. [49] examined the use of outranged passenger trains for freight transport. They suggest using available infrastructures, such as designated spaces in public transport stations and railways, during off-peak hours to accommodate freight. By shifting from road to rail, their findings show a potential 5% reduction in road freight transport resulting in a 15% decrease in emissions and a 20% reduction in congestion annually in the Sorrentina Peninsula area of Italy. Scientists of the Research Lab for Urban Transport (ReLU) analyzed the integration of a logistics tram in a pilot project that focused on parcel delivery services provided by courier, express, and parcel services (CEP). The existing tram network in Frankfurt, Germany, was utilized to transport parcels from a tram depot to a tram station in the city center where cargo bikes with special boxes were employed for further delivery. This approach offers an energy-efficient, fast, and flexible solution for delivering parcels to end customers. It is worth noting that public transportation stations with lower frequencies are better suited for such multi-purpose projects compared to highly frequented ones, as they facilitate uninterrupted loading and unloading. Additionally, it is important to consider that public transport service providers prioritize passenger transport over freight transport when using infrastructure primarily intended for passenger services to ensure uninterrupted passenger transport at all times [25; 50]. Furthermore, recent research has introduced a deep reinforcement learning algorithm that integrates both passenger and freight transport. This innovative approach achieves a 30% higher fleet utilization and a 35% increase in fuel efficiency compared to other approaches that integrate passenger and freight transport as well as concepts that use vehicles solely for one of these two aspects [28].