Vehicle Platooning

Platooning is a component of intelligent transportation system (ITS) that has been proposed as an efficient solution for highway traffic management (Bělinová et al., 2010). The main concept of vehicle platooning is that a set of vehicles move together while keeping a short distance from each other. This can boost road capacity, improve traffic management, and decrease travel time. Additionally, the safety and convenience of passengers increase due to the elimination of intense vehicle acceleration or deceleration, and the consideration of platoon vehicles as a single unit. Also, emission performance and fuel consumption are improved considerably. Any group of vehicles that move in close coordination through the headway control system is considered a platoon. These vehicles keep a small distance between themselves and maintain their relative speed. The vehicle in the forward position (the leader) indicates the trajectory and speed reference and has the responsibility of controlling all the following vehicles in the platoon. Movement instructions are transmitted from the leader to each vehicle in the platoon, either directly, or by the previous vehicle. The front vehicle controls the driving direction and the rear vehicles follow the leader using advanced attributes including adaptive cruise control, collision avoidance systems, and lane departure warning. One of the most common forms of platooning is truck platooning, which can lead to significant improvements in fuel saving; with up to 5% and 10% for the leading truck and following trucks respectively, as measured during pilot tests on public motorways. Therefore, an increase in the employment of this system for transportation networks is anticipated in the coming years (Fakhfakh et al., 2020).

Truck Platooning

Truck platooning is still in the experimentation phase. To truly clarify this vision, developed countries in Europe and North America are investing excessively in this technology. According to Eurostat, more than 75% of domestic freight transport in the European Union (EU) travels about 1,750 billion ton-kilometers by road; while in some European countries this rate has reached 90% or more. The EU is launching several novel and innovative plans under its “Horizon 2020” research to improve fuel efficiency and optimize road transport. If the platooning system is performed for just 25% of European trucks, almost one billion liters of fuel can be conserved annually (assuming a 5% fuel saving per vehicle), which could lead to a significant reduction in CO₂ emissions. North America is also working on truck platoons, initiated mainly by the efforts of prominent automakers like Daimler AG, Volvo, and other companies. Similarly, Asian-Pacific countries such as Japan and Singapore have begun platoon testing of trucks. The Japanese government is upgrading truck platooning and automation to efface its driver errors and improve transportation functionality. This country plans to present autonomous truck platooning on motorways in 2020 (Mordor Intelligence, 2020).

Platooning in the Industry

As far as the current platooning systems in the industry, several projects have commenced across different areas in order to analyze and verify automotive platooning systems. These projects consist of automotive industry members (e.g., SCANIA, DAF, Volvo, Daimler), technology companies (e.g., Peloton Technology, OTTO Motors, Omnitracs), and investment firms, in conjunction with administrative support. Peloton Technology, a connected and automated vehicle startup which works on enhancing safety and optimizing the performance of freight transportation, has specified a $60 million budget round, which is led by the fleet management company Omnitracs. The round included other well-known stakeholders such as Intel Capital, Volvo Group, BP Ventures, Nokia Growth Partners, UPS Strategic Enterprise Fund, and Lockheed Martin. In 2018, Volvo Group, FedEx, and the North Carolina Turnpike Authority (NCTA) flourished in the field of truck platooning. Volvo has been one of the main supporters of platooning for a long time, due to the fact that both freight companies and professional drivers can benefit through safer, more fuel-efficient actions. Volvo Trucks and FedEx intend to continue improving the Volvo CACC (Cooperative Adaptive Cruise Control) technology in the future, with the aim of continuing to learn about the potential advantages of vehicle platooning (Mordor Intelligence, 2020).

Last word

Vehicle platooning is one of the most important research topics of the modern era. Although several tests and investigations have been accomplished so far, the proposed platooning algorithms still pose many challenges that need to be solved. Some of the shortcomings of these algorithms are as follows; first, platooning algorithms are very intricate because of the dynamic behavior of the vehicles and the variety of operations that can occur (merging platoon, platoon split, joining platoon, etc.). Therefore, the development of theoretical models for the design of these algorithms is still an open problem that needs to be addressed (Fakhfakh et al., 2019). Second, limited studies have used a validation method to diagnose errors in platooning algorithms. One of the limitations of existing works is the employment of particular infrastructures for testing. Features of vehicle environments include high vehicle mobility and dynamics. Therefore, the use of runtime testing could be a more efficient solution for the validation of the studied systems (King et al., 2011). Third, since platooning is used in crucial environments containing various operations, a trivial error can have irrecoverable and costly consequences. Formal verification is essential to avoid design errors in platooning algorithms, and to ensure the accuracy of the attributes outlined by the designer. Although a few researchers have attempted to correct these algorithms, these projects are still in their early phases (Karoui et al., 2017). Therefore, more studies should be conducted to validate the various operations that can happen during platooning. Finally, although platooning is an appropriate solution and can lead to a reduction in travel time and fuel consumption, it has various security problems. Several research studies have mentioned the security attacks in platoons, and have proposed some strategies to alleviate their impacts (Dadras et al., 2018). However, the actual accuracy of these works has yet to be tested. Hence, employing formal approaches to provide security solutions needs to be investigated in future works.