Platooning and Blockchain — Perun as a Digital Car Tow

In this blog post, we introduce a prime use case for blockchain and Perun State Channel technology in logistics called Platooning. Platooning is a new method of driving, where multiple vehicles are linked together to a convoy. It increases economic and ecological efficiency due to slipstream effects and increases the quality of work for truck drivers because they can rest while platooning. This linkage between the vehicles is achieved electronically and allows the whole platoon to accelerate and brake according to the leading truck’s behavior. With the addition of blockchain and Perun State Channels, a fully decentralized solution can be achieved that enables direct communication and transactions between the leading and following vehicles.

Authors: Songyi Jimmy Lin, Hendrik Amler, Marcel Kaiser

What is Platooning?

The word Platoon originates from military lingo and describes a group of 40 soldiers moving closely together. In our context, a Platoon refers to truck convoys that harness efficiency effects on highways by using automated driving support systems and slipstreams in conjunction with blockchain technology.

The close proximity of the vehicles in a platoon leads to better fuel efficiency due to reduced air resistance and optimized driving in the platoon. Platooning also helps to reduce traffic congestion and thus aids to shorten commute times. Another benefit of the technology is less downtime for vehicles due to the tight linkage between vehicles that allows autonomous driving systems to take over while drivers can rest.

The introduction of higher traffic risk is not too much of a concern as the automated braking system enables platoons to drive closer to each other than human drivers. Human failure is the main contributing factor in over 90% of traffic accidents. Several cooperative adaptive cruise controllers for truck platooning have been proposed (Nowakowski et al., 2015). Vehicle-to-vehicle communication and string stability (minimized range errors) can be achieved for arbitrary platooning durations.

Figure 1: Perun as a digital car tow framework for platooning including benefits and functionalities.

It is estimated that the average fuel consumption savings which can be achieved by platoons highly depend on the distance between the trucks. The closer the vehicles drive, the higher the efficiency of the slipstream usage. While the numbers vary, the trade-off between safety and fuel efficiency is maximized at around 5 meters of distance (Muratori et al., 2017). The same study finds that also the position of the truck is relevant for the saving of fuel. The leading truck does save as well but not as much as the second and third truck. This observation is confirmed by Lammert et al. Further factors impacting fuel reduction positively are aerodynamic trailer configurations like trailer skirts. Interestingly, the speed of a platoon seems to have no large effect on the savings observed. As a consequence, platoons can help to save up to 20% of fuel for following trailers and around 10% of the leading truck’s fuel consumption. This difference needs to be compensated efficiently if platooning should ever be viable. All in all, platooning has the potential to save a relevant amount of carbon emissions.

Leveraging blockchain and Perun channels

A decentralized solution has many advantages: It is easier to collaborate with other companies, trust is put not on one but multiple shoulders, it creates transparency, reduces the risk of cyberattacks and can improve privacy aspects if combined with other technologies such as zero-knowledge proofs, SMPC (secure multi-party computation) and trusted execution environments. Especially when multiple logistic companies come together to form a Platoon, a shared state of a Platoon is necessary which blockchain technology can provide. It should be possible to join or leave a platoon freely on the highway. This introduces the challenge of swiftly opening and closing connections to precisely track the duration and distance driven.

However, saving the entire history of states on a blockchain is highly unfeasible. Therefore, second-layer technology is required. It has to be kept in mind that centralized solutions are to be avoided to allow for high interconnectivity and a minimum of fees.

The Perun framework is able to harness the potential of platoons by enabling vehicles to create a second-layer channel between them for two purposes

1. Enable the transferral of a digital car tow by sending driver’s data (with the ability to execute arbitrary logic in them)
2. Enable to pay the driver of the leading truck for their data and the opportunity for the second driver to rest

This resolves the imbalance of benefits between the two or more participants: the leading truck benefits from platooning but less than the following trucks, therefore the following trucks compensate the leading truck monetarily.

This type of channel supports offline interactions between the parties and is system-agnostic — it does not matter which DLT or non-DLT mobile payment system the trucks use — even if they are different. They work well if trucks do not know or trust each other: payments must be processed authentically, verifiably and trustlessly. This of course requires the correct distance and driven time known to the smart contract executed within channels. Once these conditions are satisfied, Perun channels are cheap and fast for their users and simplify the payment process enormously for truck drivers. In this particular case, it is important that no complicated interaction between drivers is required and they do not need to stop to perform the channel creation, otherwise, the project might end up costing more than solo driving would have.

To facilitate this process, we need to know more about the security and the key generation for each truck. Each truck is required to have two pairs of keys: one pair for an external account to pay for the platooning service and another pair to establish a connection with the platoon. The second key pair secures the connection between the trucks. To simplify the interaction with the platoon, this key can be in the form of a QR code, which will be scanned automatically without any driver input. This allows trucks to be profit centers and payment units in this ecosystem without exposing large amounts of company funds to drivers’ actions. In the end, the companies all have reduced operational costs from driver and vehicle as well as additional earnings from leading platoons from time to time, while increasing public safety and reducing carbon emissions using blockchain and state channel technology.

Oftentimes a truck delivery is completed, the delivering truck drives back empty. The shipment of nothing is highly inefficient and a heavy burden on the environment. This problem can be addressed by collaborating with other companies and decentral coordination of trucks. However, the challenge of truck-sharing is discussed in a plethora of literature and shall be discussed in another post.

Conclusion

In this article, platooning is introduced. We leverage Perun to enable trustless, decentralized offline micropayments for this use case. Due to the nature of Perun channels, different companies can easily let their transporters apply the framework to save money, the environment and their workers’ energy at the same time by sharing slipstream, automated driving and improved working conditions. Blockchain technology can play a vital role in the decentralization and coordination of transportation burden. Consortia of key players might kick off an initiative to get platoons on the roads.

Remarks

To realize this vision, feel free to contact us. The more partners reach out, the more likely it is for an impact to be made. For more information, write a mail to Marcel@PolyCry.pt. Otherwise, if you would like to generally ask questions about us or the general article, feel free to join our discord server.

If you are interested in learning more about the Perun Channel Technology and how it can be used to scale your blockchain application, visit our website (https://perun.network/) and our GitHub repo or contact us directly by writing us an email at info@perun.network.

If you want to learn more about us as a company, visit us at PolyCry.pt or follow us on Twitter (@PolyCrypt_).

References

Muratori et al. (2017): Potential for Platooning in U.S. Highway Freight Transport. SAE International Journal of Commercial Vehicles. 10. 10.4271/2017–01–0086.

Nowakowski et al. (2015): Cooperative Adaptive Cruise Control (CACC) for Truck Platooning: Operational Concept Alternatives. UC Berkeley: California Partners for Advanced Transportation Technology. Retrieved from https://escholarship.org/uc/item/7jf9n5wm