## 3 Methodology
### Data Collection and Sample Description  
In the context of an acceptance study for fips [35], data were collected between January and February 2024. Participant recruitment primarily took place through small postcard invitations sent randomly to over 100,000 households across the Mannheim urban district, supplemented by social media advertisements from rnv. As an incentive, participants had the chance to win one of 25 local gift vouchers, each worth EUR 20. The survey was designed to collect detailed information on participants' sociodemographic characteristics, their general attitudes toward RP services, and in particular, their usage behavior with respect to the nighttime RP service fips. Respondents who had previously used the nighttime service were asked to provide information about their most recent trip. Thisincluded the purpose of the trip and any complementary modes of transportation used during the outbound or return leg (e.g., walking, PT, private car). In addition, the survey also addressed non-users of the RP service. These respondents were asked to specify the reasons for their non-utilization, such as lack of awareness.  
Besides revealed preferences, a central component of the survey was a stated choice experiment (SCE), which focused on participants' travel mode choices across both daytime and nighttime scenarios, encompassing both mono- and intermodal options. This experiment forms the core of the study, providing insights into individuals' preferences for various modes of transportation under different travel conditions. The conceptual design of the survey, particularly the combination of revealed preference elements with a stated choice design, follows methodological standards that have also been applied in other studies evaluating innovative mobility services. For instance, a similarly structured empirical study was conducted as part of the accompanying research on the deployment of automated minibuses in Monheim am Rhein (2016). In total, 602 individuals participated in the survey. After applying data cleaning procedures, such as removing responses with implausible completion times and identifying straightlining behavior, a final sample of 566 participants remained for analysis. Table 1 presents descriptive statistics for different user groups, highlighting the attractiveness of the nighttime service for younger individuals. Specifically, users of the RP nighttime service have an average age of 42.9 years, making them significantly younger than both daytime-only users (51.6 years) and non-users (51.3 years). This age-related pattern aligns with the demographic profile of nighttime service users of the private RP provider MOIA, as reported by [PERSON] et al. (2017). During the sample recruitment, no quotas were aligned, but all people willing could fill out the survey, as we expected major challenges to find sufficient respondents with experience while applying quotas. Therefore, the right-hand column provides the results from the latest German national household survey Mobilitate in Deutschland to compare the current sample with ([PERSON] et al., 2017). Since only adults could participate, the proportion of employed and retired people in our sample is higher than the German average. As the data stems from 2017 membership rates for shared services are low or not available at all.  
Figure 1: Features of the fips service (Source: mv).