Wireless local area networking (WLAN)-based communication enables vehicles to exchange information that is beyond the vehicle's and the driver's direct perception. It has the potential to support various applications for road safety and traffic efficiency, such as road hazard warning and collision avoidance. As opposed to cellular mobile networks, WLAN-based vehicular communication does not require a central control or an operator; instead it uses a decentralized and self-organizing approach. This article introduces key requirements and basic characteristics of WLAN-based vehicular communication and outlines the system architecture. Furthermore, it gives an overview of the most important technology components for WLAN-based vehicular communication, covering radio and communication protocols, security and privacy, radio resource management, and congestion control. The article concludes with an overview about standardization and an outlook on the system deployment.