Has Martin Daum thrown serious rain on the platooning parade? Is he right to stop investing in the technology? Will he dissuade others from doing so?

He’s not without influence, after all. As head of Daimler’s Commercial Vehicles unit, and formerly the chief at Daimler Trucks North America, he’s a weighty fellow whose opinions are always well considered and straightforwardly expressed. He doesn’t beat around many bushes, so when he proclaimed last fall that platooning might not be worth the trouble, at least a zillion ears perked up.

Speaking at the IAA commercial vehicles show in Germany last September, he said, “When it comes to automated vehicle technology, there is a very compelling business case for these systems. However, platooning might not be the holy grail we initially thought.”

Daum allowed that past platooning tests yielded good results in boosting fuel economy on older rigs. However, more recent testing has shown that fuel-saving numbers were “not as high as expected” for newer tractor-trailer combinations with already-efficient aerodynamics.

“Therefore,” Daum added, “I am a little bit critical of platooning today, but at Daimler we will continue testing this technology and see where it eventually leads us.”

At the recent CES show in Las Vegas, “a little bit critical” became dismissal. “We will not prioritize [platooning] for series production,” he said. “We tested it for several years… Results show that we have to re-assess how much fuel is actually saved: platoons do improve aerodynamics and fuel efficiency considerably in an ideal world, but not in real-world traffic.”

Swedish truck-maker Scania would beg to differ. It seems to be more committed to platooning than ever, as do other Europeans. Which is a little odd if you think about the congested nature of roads over there and the fact that no national jurisdiction has made it legal. In the U.S., 18 states allow platooning and even Daum says the wide interstates and long highway hauls offer an ideal environment for trucks running nose to tail.

Scania says current adaptive cruise control brings a 3-4% reduction in fuel consumption with trucks traveling around 1.5 seconds apart at 100 km/h, a 40-meter gap.

“There will be further savings when we have a smaller gap and much richer information being transmitted between the trucks,” says Christian Bergstrand, a project manager at Scania, quoted on the SMMT website (SMMT represents the U.K. automotive industry, trucks included). “When we introduce autonomous technologies as well and no longer have to take the driver into consideration, we can have a really short gap. In the case where we will have one driver for a platoon of four trucks, we could cut fuel consumption by 10% or more for the time the trucks are in the platoon.”

By “really short gap”, he means 10 meters or less, which is mighty close.

In the meantime, the challenges have more to do with operational and legal matters than technical ones. Given those operational issues Bergstrand says that the early adopters will almost certainly be large fleets creating in-house platoons.

“They can plan for coordinated departures and match-make within the fleet. We want to then grow the volume so that, [in time], smaller customers can benefit from more ad hoc platooning.”

The latter is a very big challenge, matching trucks from different fleets on the fly, not least because they would very likely have different levels of maintenance care and braking power. I guess the various electronic tricks would iron out those differences, but we’d be using lowest-common-denominator logic.

“The requirements have not been defined that would determine a possible introduction in, say, three to five years. Even so, I strongly believe that before 2025 we will have many semi-autonomous platooning trucks on European roads,” Bergstrand concludes.

Daum seems not to agree.