Abstract: Vehicular networks or Vehicular Ad Hoc Networks (VANETs) are likely to become the most relevant form of mobile ad hoc networks. Vehicular ad hoc networks are one of the most interesting research areas due to high node mobility and fast topology changes. They can provide a wide variety of services ranging from safety-related warning systems to improved navigation mechanisms as well as information and entertainment applications. These diversified applications give rise to a lot of challenges including network architecture, vanet communication protocol, routing mechanisms as well as security issues. In this study, researchers review the standardization work and researches related to vehicular networks and discuss the challenges facing future vehicular networks.