The US Department of Transportation reports more than 1.8 million intersection crashes per year. In 2003, there were 42,643 fatalities. Europe reports similar statistics with 1.7 critical injuries and 40,000 fatalities per year. The annual costs associated with traffic accidents total nearly 3 percent of the world's gross domestic product (GDP) and are bound to increase with the growth of the number of vehicles. The potential of Intelligent Transportation Systems and Vehicular Networks in saving lives and facilitating traffic is prompting their rapid development. With all of their promise, Vehicular Networks whereby vehicles and infrastructures are connected through wireless networks exchanging valuable information present two major risks that must be addressed: (1) highly dynamic networks of communicating vehicles and highways can be vulnerable to attack and abuse if security concerns are not adequately analyzed and addressed; and (2) highly dynamic networks can be easily overwhelmed even by a small number of queries if these queries are not efficiently optimized and planned. The objective of this research is to develop methods and algorithms that ensure that vehicular network services meet all safety requirements, including accountability, privacy, authenticity, and timeliness. In particular, the following three areas of research will be pursued: 1. The development of authentication and key agreement protocols preserving privacy while ensuring accountability that are adapted to the requirements and constraints of vehicle to infrastructure communications. 2. The development of vital signs authentication algorithms that allow vehicles to verify the authenticity of information received from neighboring vehicles. 3. The development of query optimization methods that take advantage of data and time redundancy to obtain accurate information with minimal communication overhead, thus ensuring timeliness. This research will be conducted at Oakland University, located in Automation Alley, home to all major automotive manufacturers, suppliers and developers. This project will help increase security awareness in automotive systems and the future vehicular networks. The symbiotic relationship between Oakland University and the automotive industry will accelerate technology transfer and promote validation and testing of the theoretical results in realistic settings.