## 1 Introduction  
A cooperative vehicle-infrastructure system is a hybrid vehicular network, composed of mobile vehicles and fixed roadside units. The vehicular nodes are equipped with GPS modules, various sensors (e.g., the speed sensor, the road condition sensor, and the inter-vehicle distance sensor), and the wireless communication interfaces to support the dedicated short-range communications (DSRC) [1]. In addition, the roadside units have more powerful computing capability, communication capacity and storage capacity, and often take the role of the internet access points because of their robust and reliable connections via wired links or long-distance high-bandwidth wireless links [2; 3]. As a key technology in intelligent transportation systems, vehicular networks work for the safe and comfortable driving, the traffic monitoring, the multimedia sharing and so forth, with the provision of vehicle-to-vehicle (V2V) communications and vehicle-to-roadside-unit (V2U) communications. Data acquisition in vehicular networks is an important and challenging task due to the various user requirements and the complex network environments. There are lots of practical issues to overcome, such as how to utilize cloud resources and information-centric networking to improve multimedia delivery [4; 5], how to circumvent driver distraction when manipulating built-in applications [6], and how to design a smart car with ubiquitous computing and intuitive human-computer interaction [7]. Additionally, smart applications like E-health based on the internet of vehicles are promising future domains [8]. For the content queries sent by the vehicular users, if the mobile vehicular nodes download the contents from the internet directly, a drainage of network resources and severe access congestion are inexorable consequences. Thus, recent research focuses on how to replicate and distribute the contents to vehicular nodes or roadside units in vehicular networks [9]. Although a vast majority of existing studies do research on the content distribution at vehicular nodes, more and more evidence shows that the opportunistic contact chances and the short communication durations in companies with the security risks of autonomous mobile nodes [10] severely restrict the performance enhancements. Therefore, in a cooperative vehicle-infrastructure system, the roadside units with rich resources, such as the storage spaces and the communication bandwidths, may improve the data distribution and provide better data services. In our previous work [11], we briefly introduced a content replication scheme using roadside units as content carriers. However, with respect to the cooperation of vehicles and roadside units, there is still room for improvement. This article puts forward an efficient data acquisition model using stable matching of bipartite graph, namely DAS, aiming for a polynomial-time solution which combines the metrics, i.e., the access ratio and the access delay, by problem formulation. A sketch map of a content request and acquisition process in our model is displayed in Figure 1. A roadside unit \(u_{1}\) obtains a request from a vehicle \(v_{1}\) at time \(t_{1}\), and forwards this request to the internet. Then, the online control center computes a content distribution solution and allocates the data to another roadside unit \(u_{2}\) accordingly. Thereafter, \(u_{2}\) responds to \(v_{1}\) at a later time \(t_{1}+\Delta t\). In this process, the content distribution solution is a key part affecting the performance of data access, which is determined by the network states, i.e., the requests from vehicles, the storage of roadside units and the vehicle route planning. In this article, through taking the contents as the left vertices and the roadside units as the right vertices in a bipartite graph, and then calculating a preference ranking or a priority ranking for each vertex over vertices in the other side, a stable data distribution solution is obtained, which considers the access ratio metric and the access latency metric together.