Wide area wireless communications such as cellular-type networks and personal communication services (PCS) have been deployed successfully worldwide mainly for voice communication services. Recently, however, applications are rapidly expanding towards a rich array of data communications capabilities that include wireless Internet and video downloading. Moreover, traffic and alerting information has been carried out to drivers through cellular networks and broadcasting systems. Current and emerging air interfaces are designed to provide broadcast, multipoint multicasting, point-to-point, vehicle-to-vehicle, and vehicle-to-point communications that can be utilized in the ITS sector. These technologies are designed to enable quasi-continuous communications, or communications of protracted duration, between vehicles (or mobile terminals) and service providers, or between vehicles/mobile terminals and other entities. As such they are complementary to dedicated short range, single point technologies standardized in various regions of the world.