Vehicle Ad hoc Networks (VANET) emerged as a subset of the Mobile Ad hoc Network (MANET) application; it is considered to be a substantial approach to the Intelligent Transportation System (ITS). VANETs were introduced to support drivers and improve safety issues and driving comfort, as a step towards constructing a safer, cleaner and more intelligent environment. VANET has some unique characteristics compared to MANET; specifically it includes high mobility and constrained patterns restricted by roads. Many challenges have emerged in VANET, encouraging researchers to investigate their research in an attempt to meet these challenges. Routing protocol issues are considered to be a critical dilemma that needs to be tackled in VANET, particularly in a sparse environment. This book introduces an efficient routing mechanism that impacts on enhancing network performance in terms of disseminating messages to a desired destination, balancing the overhead on the network and increasing the ratio of packet delivery with a reduced time delay. Moreover this book presents an On Board Unit (OBU) architecture for sending HELLO beacon messages adaptively in VANET based on the context aware system.