# An Overview of Shared Mobility Operational Models in Europe
## 4 Bikesharing  
Bikesharing is a service in which bicycles are made available for shared use on a short-term basis. According to [9], bikesharing is simply \"the shared use of bicycle fleet\" and \"a short-term bicycle access, which provides its users with an environmentally friendly form of public transportation.\" It is one of the most popular transportation modes that has been introduced in an increasing number of cities in Europe, Asia, and North America [52]. Bikesharing is a perfect solution to the first- and last-mile problems [9; 53], and by today's technology, they are completely self-service and available any day of the week [52]. There are four key phases of generations in bikesharing [54; 55]:  
* First generation: white bikes (free system)
* Second generation: coin-deposit systems
* Third generation: IT-based systems
* Fourth generation: demand-responsive, multimodal systems. Other authors, such as [9; 56; 57], also follow the same principle of defining these generations. The first attempt at sharing bicycles, also known as \"White Bikes\", began in Amsterdam in 1965. Fifty bicycles were painted white and left unlocked throughout the city for anyone to use for free. Unfortunately, within a month of the start of that initiative, all 50 bikes were destroyed or stolen, thus ending the first generation of the public bike system [58]. After the first failed generation, caused by the lack of security, the second generation was developed with a secured approach to the bikesharing system. This was improved by having coin-deposit docking stations, although the low fee for coin-deposit meant that bikes were often taken and never returned [54; 57]. Third-generation IT-based systems leverage wireless and electronic communications for tracking, drop-off, and bicycle collection. The adoption of debit and credit cards has increased user responsibility. Third-generation bikesharing consists of docking stations, advanced technology (such as smart cards, smart keys, and magnetic-stripe cards), kiosks, or user interface technologies for check-in and check-out. Despite costing more than first- or second-generation systems, these systems provide significant advantages due to the revolutionary technologies they incorporate. IT enhances system management, discourages bike theft, and allows public bikesharing systems to track bicycles and access user data. This is responsible for the recent growth in the scope and locations of public bikesharing [54; 57]. The technology of third-generation systems is expanded by fourth-generation demand-responsive multimodal systems. These systems incorporate improved features that help improve user metrics, like clean, flexible docking stations or \"dockless\" bicycles; demand-responsive bicycle redistribution innovations to help system rebalancing; value pricing to encourage self-rebalancing; multimodal access; billing integration (e.g., sharing smart-cards with public transit and carsharing); real-time transit integration and system data dashboards; and GPS tracking. For instance, a lot of B-cycle programs (including those in Boulder, CO, Broward County, FL, Denver, CO, HI, Madison, WI, Omaha, NE, and San Antonio, TX, USA) use GPS telematics for real-time tracking. Although all of these features are enabled by IT, fourth-generation bikesharing is considered a standalone phase due to its integration with wider mobility systems and its shift toward data-driven, demand-responsive operations. These systems utilize real-time usage data and predictive analytics to dynamically optimize bike availability, station balancing, and user experience based on actual demand patterns. The idea of fourth-generation bikesharing is still in its infancy and has not yet reached its full potential [54; 57]. Considering everything, the development of bikesharing systems has evolved from basic, unprotected bike access in the first and second generations to IT-enabled management in the third, and then to fully integrated, data-driven, and demand-responsive mobility solutions in the fourth.