The European Commission has been urged to come down on the side of C-V2X in the standards war embroiling V2V and V2X communications by a sizeable group of major auto OEMs, telcos and infrastructure providers. The more interesting wider aspect is that urgency highlights the emergence of platooning as the likely first commercial realization of autonomous driving with potentially significant fuel savings for fleet operators – combined with reductions in congestion.
Platooning saves fuel costs by exploiting the same aerodynamic factors that make longer trains more efficient than shorter ones, the same one that racing cyclists exploit by shielding their best rider behind others to reduce air resistance. According to the European Union (EU) SARTRE project, running between 2009 and 2012, fuel and CO2 emissions can be reduced by 20% through platooning. In that project the platooning involved conventional vehicles being driven by human drivers, but when aided by V2X communications, the aim is to allow whole convoys to react as one with potential for greater safety, while also reducing gaps between vehicles so that congestion is eased by smoother traffic flow.
There are several ongoing projects involving platooning. Logistics giant FedEx has just announced it is using advanced driver assistance system (ADAS) technology to conduct lorry platooning tests on trunk roads, as part of its research collaboration with Volvo Trucks and the North Carolina Turnpike Authority (NCTA). They claim this to be the first demonstration of platooning technology on public highways between a major lorry maker and a transportation company in the US, and certainly we do not know of any other.
At this stage, it is a small platoon comprising three professional lorry drivers in Volvo VNL tractor units, each pulling double 8.5-meter trailers. This uses a wireless protocol developed specifically for platooning called Cooperative Adaptive Cruise Control (CACC) enabling the vehicles to travel at 100 kmph (62.5 mph) while keeping a time gap of 1.5 seconds, which equates to a closer distance than typically recommended for lorries or any other vehicles. The trial includes staged and unplanned cut-ins by other vehicles to demonstrate resilience against common traffic situations.
This was the culmination of research collaboration ongoing since April 2018, involving three Volvo VNL tractors paired with various combinations of FedEx trailers to simulate real-world routes and trailer loads. The potential benefits of platooning that are being studied during this collaborative research include faster responses to hard braking, while maintaining safety and fuel efficiency.
Another rather similar pilot project just announced has been taking place in Germany between DB Schenker, the logistics arm of German rail operator Deutsche Bahn AG, and commercial vehicle maker Man Truck & Bus, with help from Hochschule Fresenius University. This project, on the A9 highway in Germany, involved a two-lorry platoon setting off from the DB Schenker branch office in Neufahrn near Munich to Nuremberg.
Regular test runs were made along this 145 Km route, with loads to be added in August 2018. After that, the platoons will be on the road every day, making up to three routine logistics trips and laden with part loads of machine parts, drinks and paper. Again, this is the first public demonstration of platooning in Germany, aided by federal funding of around €2 million. Apart from the technology itself the participants are focusing on how best to integrate it into the logistics chain and also on the psychosocial as well as neurophysiological effects of platooning on the drivers.
For platooning to operate on a large scale, especially when V2X communication has to be integrated, there will have to be agreement on the protocols used, unlike in these trials. That is why a major group has been exerting pressure on the EU to come down on the side of C-V2X, which is the cellular version dovetailing with LTE and ultimately 5G if that ever happens. Signatories to a letter urging for the Commission to back C-V2X include BMW, Daimler, Ford, PSA Groupe, SAIC Motor, Deutsche Telekom, Telefonica, Vodafone, Ericsson, Huawei, Intel, Qualcomm, Nokia, Samsung and Savari. That is quite an influential group, but there is plenty of support for the alternative from the Wi-Fi camp ITS-G5 – which is based on 802.11p.
There is also the standard widely deployed in the US for dedicated short-range communications DSRC, but that uses the 5.9GHz waveband forming the basis of the European ITS-G5 standard and so is a close sibling. Outside the US, especially in Europe and China, C-V2X has been gaining more traction, but not universally, with Siemens arguing in a paper that ITS-G5 is more mature and meets all the key requirements of V2V and V2X communication while C-V2X does not, or did not at the time that paper was written.
Such features include ability to operate in a very dynamic environment with high relative speeds between transmitters and receivers and support for extremely low latency below 50ms in safety-related applications for the so-called pre-crash sensing warning message. It is also necessary to tolerate the high load generated by the periodic transmission of multiple messages by many sources and the high vehicle density typical of congested traffic scenarios, which will be the case given widespread commercial deployment. Another point is that some V2X messages are local and most critical to nearby vehicles and irrelevant to those further away, while others have wider relevance, so there must an intelligent filtering mechanism.
The group lobbying the EU focuses on compatibility, arguing that ITS-G5 would lock vehicle makers into a technology “which, despite its name, has no relationship to 5G technology and certainly no evolutionary path toward compatibility with 5G”. They contend support for ITS-G5 would place Europe at an economic disadvantage compared with China and the US, where C-V2X is emerging as a strong technology candidate for C-ITS (Cooperative Intelligent Transport Systems). This seems to ignore the traction in the US behind DSRC, although there is growing momentum even there behind C-V2X.
As always in these standards wars it is not necessarily the best that wins, with a lot of politics involved and in this case, it does look as if C-V2X is gaining the upper hand.