# Layout Model of Bike-Sharing Facilities in the Transfer-Influenced Area of a Subway Station
## 1 Introduction  
In the context of the development of sustainable transportation, low-carbon travel modes such as cycling and walking are becoming more and more popular. In sustainable transportation plans, cycling and walking are alternatives to the motorized transportation system [1]. Many countries are increasing investment in infrastructure construction for pedestrian and bicycle travel. However, pedestrians and cyclists are vulnerable in the road traffic system. Safety issues are an important factor hindering the use of bike lanes on urban roads [2]. There is an increasing number of studies on the treatment of pedestrian and cycling mobility issues in the urban environment. [PERSON] et al. proposed an original estimation method for cycling flow, taking safety into account in cycling infrastructure layouts [3]. They also proposed an original risk-based methodological approach for pedestrians [4]. Systemic pedestrian safety management processes can reduce pedestrian accidents [5]. Some scholars have proposed a forecasting model for estimating pedestrian flow in the network, which can be used in measures to protect vulnerable road users [6]. In the sustainable development of cities, the two modes of walking and cycling still have great potential. After the advent of bike-sharing, the availability of bikes and the flexibility of bike routes have been significantly enhanced. Bike-sharing has developed on a large scale in China [7]. Bike-sharing has greatly satisfied the needs of short-distance travelers because of its convenient, fast and efficient characteristics. Bike-sharing has become the most flexibletransfer mode of urban rail transit. With the development of urban rail transit networks, \"rail transit + bike-sharing\" has become an important trend in the future development of urban multi-mode combined travel [8]. However, mass investment without planning in the early stages has directly resulted in a significant waste of resources, and the efficient \"rail transit + bike-sharing\" model was unsustainable. In order to further promote the development of the \"rail transit + bike-sharing\" mode, bike-sharing has gradually stepped into a new stage involving fixed-point borrowing of pile-free facilities and refined delivery management. At the same time, there is also a series of derivative problems; for example, the layout of bike-sharing facilities is not convenient enough, there is no effective network among bike-sharing facilities, and shared bikes are randomly parked in the area near subway stations [9]. These problems pose higher challenges to the layout and construction of bike-sharing infrastructure in the future. The layout of bicycle facilities mainly includes two problems. One is the determination of public bicycle parking piles, drop-in points and electronic fences of shared bikes. The other is the determination of the scale of bike-sharing facilities and the number of shared bikes. Previous studies on bike-sharing management mainly focus on the bicycle rebalancing scheduling problems of bike-sharing systems [10; 11]. Moreover, studies on public bicycle parking locations and allocation are relatively comprehensive [12; 13; 14]. Some researchers have also considered the location and the allocation of public bicycle systems. [PERSON] [15] established an optimization model of parking location, parking pile configuration, bicycle allocation in each period and rebalancing scheduling decisions. [PERSON] [16] considered parking location, bicycle allocation and rebalancing scheduling problems under the mixed use of ordinary and electric bicycles, and established a mixed-integer linear programming model with the goal of maximizing income. [PERSON] [17] put forward the method of urban public bicycle location, considering the influence of newly added public bicycle stations from the perspectives of decision makers and users, and then constructed a bi-level programming model.