Platooning of connected automated vehicles on freeways: a bird's eyeview

A platoon can be defined as a group of consecutive vehicles that exchange information, so that they drive in a coordinated way, allowing very small spacings and still travelling at relatively high speeds. The concept of vehicle platooning is not new. In fact, scientific articles on platooning were published as early as the 1970s, and the first large-scale pilot test on platooning was carried out at the end of the 1990s. The main purpose of these early research works was to improve traffic efficiency and reduce consumptions, as well as to develop the existing technology. These contributions were very valuable, although somehow limited by the relevant technology still being in its infancy. Precisely, the development of technology and communications in the last years has given new ímpetus to research on vehicle platooning on freeways as one of the possible forms: of cooperation among connected automated vehicles (CAVs). The point of view of these recent studies has also been extended: in addition to traffic efficiency, the role of platooning is analyzed in terms of safety, sustainability, business productivity, etc. In this context, there are today many scientific publications on vehicle platooning with different purposes, set in distinct scenarios aud based on diverse vehicles and technologies (regular or segregated lanes, cars or trucks, vehicles with different SAE levels, etc.). In order to organize and consolidate the existing knowledge, a comprehensive and systematic review must be performed. This work represents a first approximation to this more ambitious objective. Firstly, platooning has been conceptualized in order to facilitate its analysis and comparisons among studies. Secondly, key publications on platooning have been analyzed to detennine the most significant impacts expected from its implementation. Finally, sorne important research gaps and disparate findings on the topic have been identified.