A transportation system is an environment that poses several challenges with regard to technology requirements. Because of the large number and high speed of Vehicles, technologies for Vehicular Communications (VC) and Intelligent Transportation Systems (ITS) must be scalable and robust enough to cope with these characteristics. Architectures and protocols for ITS thus need to be deeply examined and assessed for performance and scalability before their final adoption as part of a standard ITS framework.
Security and protection of business assets within the ITS framework is also a viral part without which the whole system can not be deployed in real life. Security is needed to provide authentication, integrity protection and confidentiality of information within the ITS framework. Without it, malicious entities may alter the normal operations of ITS applications and cause faults that can lead to disasters. On the other hand, a proper management of authorization for services and accounting is necessary in order for service providers to be able to deploy commercial services such as Internet access and multimedia streaming.
IEEE trial-use standard for wireless access in vehicular environments - security services for applications and management messages
Defines a public-key-infrastructure (PKI)-based approach for securing messages sent in a vehicle-to-vehicle and vehicle-to-infrastructure fashion. The standard is not freely available yet you can purshase it here. Some information on IEEE 1609.2 can be found here.
SeVeCom (Secure Vehicular Communication) is an EU-funded project that focuses on providing a full definition and implementation of security requirements for vehicular communications.
The project delivarable Sevecom_Deliverable_D2.1_v2.0 explains the use of public key cryptography with with pseudonymity to provide security services while preserving privacy.