This chapter provides a basic knowledge Vehicular ad hoc networks (VANETs) and to review state-of-the-art methods tackling the challenges as well as to present some directions for future research. VANETs are a special type of mobile ad hoc networks where wireless-equipped vehicles form a network spontaneously while traveling along the road. In safety applications, the goal is to improve the life safety level of passengers by exchanging safety relevant information between vehicles. Connectivity is the primordial condition for message exchange in any network including VANETs. In a mobile network, connectivity is mostly affected by the mobility pattern of nodes. Data dissemination is referred to as the process of routing and forwarding information originated from a vehicle termed as the source to another vehicle termed as the destination. Topology-based routing protocols work based on the concept of links and use links’ information to forward data/warning packets.