## 2 Theoretical Background of Bike-Sharing Systems
### Bike-Sharing System in the Light of Scientific Research  
Bike-sharing schemes have been the focus of extensive scholarly research, reflecting their growing importance within urban transportation systems. Researchers have explored a wide range of topics, including economic impacts, environmental contributions, social dimensions, technological innovations, and health-related outcomes. These diverse perspectives highlight the multifaceted nature of bike-sharing systems and point to areas requiring further investigation--particularly the role of infrastructure and its influence on user perceptions and system performance. From the economic perspective bike-sharing systems have been extensively analysed, with research highlighting their potential to generate cost savings for users, stimulate local economies, and address challenges related to financial sustainability. Scholars have examined various aspects, including cost structures, funding models, and the broader economic impacts of bike-sharing on urban mobility and development. A significant area of research concerns the financial viability of bike-sharing systems, which often depend on combination of user fees, public funding, and private sponsorship. [PERSON] emphasised the importance of public-private partnerships (PPPs) in ensuring the long-term sustainability of these initiatives, noting that municipal subsidies or corporate sponsorships are frequently required to offset high operational costs. For instance, New York City's Citi Bike programme is supported by a sponsorship from Citibank, which covering maintenance and expansion expenses [43]. Similarly, research by [PERSON] et al. highlighted that many bike-sharing programmes are unable to rely solely on user-generated revenue, particularly during the initial years of operation [44]. Adaptive pricing strategies have also been examined as a means of balancing affordability with profitability. [PERSON] et al. found that platforms offering a combination of subscription models and pay-per-use charges tend to attract a more diverse user base [45; 46]. Striking the right pricing balance is inherently challenging: excessively high fees may deter potential users, while heavily subsidised schemes can lead to financial instability. [PERSON] and [PERSON] noted that, although subsidies can improve system accessibility and equity, they may unintentionally foster dependency, thereby reducing operators' incentives to innovate or lower operational costs [47]. Beyond their financial frameworks, bike-sharing systems have demonstrated notable economic benefits for users. They provide a cost-effective solution for short-distance travel and last-mile connectivity, helping to reduce transport expenses--particularly in urban areas characterised by high living costs or limited access to public transport. [PERSON] et al. highlighted that bike-sharing is particularly advantageous for individuals who rely on multimodal transport, offering a flexible and affordable means to address urban mobility gaps [48]. Bike-sharing programmes also contribute to broader urban economic activity. [PERSON] et al. found that bike-sharing systems in Canadian cities improved access to local businesses, especially those located in commercial areas near docking stations [49]. Similarly, [PERSON] et al. observed that bike-sharing fosters tourism by offering an economical and convenient way to navigate urban spaces, thereby increasing revenue for restaurants, shops, and cultural institutions [50]. Moreover, these systems stimulate job creation in areas such as fleet maintenance, software development, and customer support, thereby amplifying their economic impact. [PERSON] and [PERSON] demonstrated that investments in bike-sharing frequently generate a multiplier effect, supporting growth in related sectors while enhancing overall urban liveability [51]. From an ecological standpoint, bike-sharing programmes are widely recognised for their environmental benefits, positioning them as a key component of sustainable urban mobility strategies.