Sometimes, boring is good. When you’re dealing with 70,000 pound double-trailer FedEx trucks, boring isn’t just good, it’s fantastic. In the world of trucking, excitement usually means expensive or dangerous trouble. That’s how you could tell that Volvo’s relatively boring public demonstration of truck platooning was so successful: it hardly looked like anything was happening at all.

But, of course, there was a lot happening. And, if you think about it in the right way, it’s not really boring at all—it’s a fascinating innovation for trucking safety and efficiency that hints at a possible autonomous future.

For now, though, the demonstration had three trucks, each with drivers, but with the lead truck controlling the brake and throttle of the two behind.

In case you haven’t updated your trucker jargon since you learned that CB slang for a Volkswagen Beetle is “pregnant roller skate,” I should explain that “platooning” refers to the process by which a series of trucks drive in (relatively) tight formation, with the lead truck assuming at least brake and throttle control over the following trucks sort of like a wireless road train.


The advantages of platooning are primarily twofold: safety and efficiency. Volvo was quite insistent that safety was their top priority in the development of a platooning system, and the safety advantages are significant.

Because of the sheer mass of a truck, every possible fraction of a second is important when it comes to braking distance, which, of course, is crucial in the all-important factor of whether or not you get hit by a truck. A platooned series of trucks helps mitigate potential wrecks by transmitting the lead truck’s braking reactions to the following trucks nearly instantly, allowing trucks to quickly react to situations that under ordinary circumstances they may not have even been able to see.


In addition to the safety aspect, there are genuine fuel economy gains to be had by platooning. When trucks can follow one another, they can use the lead truck to draft them through the air for less wind resistance and, as a result, improved fuel economy.

Trucks platooning with a 1.5 second stopping distance between them can see gains of around 5 percent, and if that distance is tightened up to about a one second distance to the truck in front, gains of up to 10 percent can be achieved. For large truck fleets, this can translate into significant savings.


Volvo announced it would be partnering with FedEx in the development of platooning technology, which is why the demonstration trucks used the dual-trailer setup common to FedEx. FedEx stuck to a company line that safety was their primary concern and motivation for their participation in the project, but the potential for 1o percent fuel economy improvements across their vast fleet is clearly a significant motivator.

Technically, Volvo has what appears to be a very well-developed and tested platooning system. Right now, the system only controls the same behaviors of the truck as an adaptive cruise control system would: throttle, brake, and distance to the vehicle/object in front of it. Steering controls are not currently implemented, but could possibly be in the future.

The basic hardware needed for platooning-ready trucks isn’t really that exotic and leverages the truck’s existing adaptive cruise control system and actuators to work. Additional hardware mounted on the exterior of the truck can be seen here:


... and internal hardware here:

The Dedicated Short Range Communication (DSRC) antennae are part of a line-of-sight system with a range of about one kilometer. These are what broadcasts the data packets (at 5.9 GHz, compliant with SAE standards J29-45 and J27-35, if you’re building your own) that send out a bunch of information between the trucks, including brake and throttle activity and position from the lead truck, GPS and other location data, radar rangefinder data, and more all at 10 times a second.


This system allows a number of trucks—really, it could be any number, but research has shown that three is about as long a “train” as most general traffic can deal with before it feels like a giant moving wall—to communicate with one another, one establishing a lead position, and the other two being driven into formation behind it, at which point the platoon can be established, and the lead truck’s driving inputs will control the trailing trucks.

As far as I know, if approved for general use, this would be the first allowed instance of a motor vehicles on public roads being controlled with inputs from an entirely separate vehicle, which is a big deal.

Yesterday’s test happened on a stretch of NC 540, a public, currently in-use highway that has been designated for this sort of testing. I rode along in the middle truck in a platoon and in a chase vehicle that drove alongside the platoon of trucks, and cut in between the platoon to see how the system reacted and failed over to conventional adaptive cruise.


These tests were, as I said, pretty boring, which is exactly the outcome you want.

Volvo’s platooning system, as I’ve seen it in operation, works just fine. I could watch on a display (which I’m not allowed to show yet) how the trucks communicate to one another via the V2V network, establish a platoon, and then seamlessly the lead truck takes over.

The driver still steers, but all brake and throttle is handled by the lead truck. It feels sort of like adaptive cruise, but a real truck driver in the front truck is calling the shots, which means any inputs (like emergency braking) happen for all trucks at once.


When the chase car cut into the platoon, the system gave the driver a warning, failed over to ACC, and that was it. No drama, no mess. When the car moved out of the platoon, the system understood and began the platooning process over again.PNIK

The distance between trucks I rode in was a pretty conservative 1.5 second gap. Gaps are measured in time to cover the distance, because that’s what’s most important here. The system, as I mentioned before, can work with smaller gaps, but one second is likely the most we’ll see on public roads.


Volvo makes it very clear this is an aid for human truck drivers, not a system designed to replace them. In that context, it’s perhaps less exciting than a fully autonomous truck, but it’s also much closer to being actually ready for deployment, and much more likely to be approved for public roads in the near future.

One question no one had a good answer for is about the possible cross-company use of platooning systems. If there’s real safety and fuel economy advances, shouldn’t this be available for any three trucks from any maker/carrier to be able to find one another on the road and set up ad hoc platoons?

I’m guessing this may be unlikely, as it’s a competitive advantage as well as a more altruistic safety advantage, and we know how big companies work. So, even if a Volvo truck operated by FedEx may have a compatible system as a Peterbuilt UPS truck, it’s not likely we’ll see many mixed-origin truck platoons any time soon.


Still, it’s all interesting stuff, and is a good demonstration of the sort of rational, evolutionary developments that happen, without a lot of crazy fanfare, in the get-shit-done world of trucking.