Overview

Given the sensing and computing power on today s vehicles, each vehicle on the road is a storehouse of valuable information about current travel conditions. If only we could harvest this information and put it to good use! This is the premise of floating car data (FCD) systems, which are a subdomain within CVHS.

The rather bizarre term FCD refers to the concept of collecting information from vehicles as they go about their normal business (i.e., floating) through the road network. As this field is still maturing, another term probe vehicles is also used to mean essentially the same thing. Data is collected that is relevant to traffic, weather, and safety, with each message also including time and location. A central entity then assimilates and processes that data and distributes results to travelers and road authorities to support traveler information, road management, and safety. In essence, the information horizon for travelers is extended beyond the tens of meters provided by sensors, and beyond the hundreds of meters provided by intervehicle communications, to the entire road network. In this way, FCD systems are CVHS with the broadest coverage.

For instance, by collecting speed and location data from vehicles, the presence of traffic congestion can be easily determined. One or two vehicles that report sudden slowing could be doing so for any number of reasons. However, when dozens of them report the same speed profiles, a high certainty is gained as to the traffic picture. Thus, by averaging data from many vehicles, the overall...