Intelligent Transport Systems (ITS) promises to be one of the most dynamic and innovative specialization fields over the next decade. Several emerging applications for vehicular wireless networks have been proposed in the recent years. Among them, safety applications have received the most interest. Road safety applications require efficient broadcast transmission of position information to surrounding vehicles. Car manufacturers currently adopted a modified WLAN IEEE 802.11(802.11p) technology for vehicular environment to support the transmission of such safety messages. This book examines this vehicular WLAN called ITS-G5 in various conditions and devise test procedures using ITS equipment named OBUs. This leads us to investigate the impact of environmental and radio factors on its performance. Firstly, a testbed is deployed under controlled conditions to test the 802.11p by means of packet generators. Secondly, CAM safety message is emulated and transmitted using IPv6 socket programs for OBUs communication. Finally, some static and mobile scenarios are tested by a BMW and using the CAM. This book set out a path for those who are interested to deal with vehicular communications.