Across the United States, a final-mile delivery network tends to work in a familiar way: a small truck, a short route and one person in the cab. The U.S. Army operates a similar network, but with greater hazards for both the route and the person in the vehicle. Harbinger, the Garden Grove, Calif.-based maker of electric and hybrid medium-duty chassis, is supplying prototype trucks designed to address what the Army calls the last tactical mile.

The effort began with American Rheinmetall, which received an 18-month Army contract on July 31 for Project Sustainment. The program is intended to field hybrid-powered uncrewed ground vehicles that move supplies to and from the forward line of troops. American Rheinmetall is the prime contractor, while Harbinger is a tier-one supplier building the platform. It is Harbinger’s first defense contract.

What Harbinger is delivering is not a truck with the driver removed. There is no cab, no steering wheel and no pedals, meaning no Soldier can take over if the autonomy fails.

“This is an AGV product. There’s no steering wheel, there’s no pedals. It is not optionally manned. It is a moving trailer-like platform,” said John Harris, co-founder and CEO of Harbinger, in an interview with FreightWaves.

From the doorstep to the last tactical mile

The Army’s resupply structure already resembles a distribution network. Main supply trains haul bulk material to brigade or battalion level, then those stocks are pushed down to company-level formations. The final leg today is typically handled by a five-ton truck or a deuce-and-a-half carrying Soldiers.

“They’re really looking at how do we take that five-ton, deuce-and-a-half type size vehicle and how do we remove some of the Soldiers from doing that very exposed mission set,” said Adam Horton, director of business development at American Rheinmetall, in an interview with FreightWaves.

The Army considers that mission one of the dull, dangerous and dirty jobs it wants to automate. In doing so, the military is drawing from civilian last-mile delivery models, but with a much tougher operating environment: roads may be unmarked, the route may sit under threat and the vehicle has to work without the support network a commercial fleet can rely on.

“It’s taking a lot of cues from what Amazon, UPS, FedEx are doing where you have those smaller trucks that are getting out there to go that last delivery mile if you will,” Horton said.

Harbinger builds Class 4 through Class 6 chassis, and Chris Haag, vice president for business development and strategy at American Rheinmetall, said the Project Sustainment vehicle is based on “kind of a Class 5 / Class 6 type truck which does door-to-door delivery at that last tactical mile commercially.”

Silent running inside the drone kill zone

The first important distinction is that these vehicles are hybrids, not battery-electric trucks.

“There’s no EVs in this contract, only hybrids,” Harris said.

The platform uses a series hybrid architecture that can operate in either mode. Harbinger’s plug-in hybrid chassis is rated for up to 500 miles commercially, and that range helps determine how far behind the front line the supply node can be placed.

“When we’re within the sort of drone kill zone, the 20 to 30 miles of the front line, it’s very compelling to be able to run as an EV, but we also don’t want to have to refuel or reload the vehicle only 30 miles out,” Harris said.

Electric mode provides concealment in a modern combat environment shaped by thermal imagery and electronic warfare.

“We can have near-zero noise, near-zero thermal signature, all of these things that make it a really compelling platform to move up to the front line for sustainment purposes without being a huge obvious target because it’s an engine running,” Harris said.

The receiving unit has no fuel supply, maintenance bay or recovery asset, so if a vehicle breaks down at company formation, it remains there. That makes reliability and route handling central to the concept, since the truck has to manage the same kinds of delivery demands a commercial vehicle would, but without the infrastructure that usually backs one up.

“You’re not going on hardball roads with lanes and markers,” Horton said. “So the autonomy has to be much more robust in order to accomplish that mission.”

Built by-wire from day one

Harbinger’s role in the program is rooted in design choices it made before it had a defense customer. The chassis was engineered from the start with steer-by-wire and brake-by-wire systems, as well as redundant power.

Vertical integration gave the company both cost control and capability, and the actuation hardware needed for autonomy is already built into the vehicle.

“If we hadn’t vertically integrated, if we’d said we’ll just go to a big steering supplier and buy what they’ve got, it would have been more expensive and dramatically less capable, because there just aren’t systems off the shelf that have this kind of by-wire functionality, in particular in the commercial vehicle segment,” Harris said.

Everybody’s piece of the puzzle

Four companies are involved in the contract, and each has a separate role. Forterra provides cross-country Level 5 autonomy for terrain without roads or lane markings. Primordial Labs supplies Anura, a natural-language interface designed to allow hands-free operation and improve the Soldier-to-robot ratio. American Rheinmetall adds defense-specific hardware and holds the contract.

That division of responsibilities is also what allowed a commercial truck builder to enter the Army market without creating a separate defense unit.

“There’s a lot that goes into a defense contract besides just making stuff,” Harris said. “We have this contract set up in a way that has allowed Harbinger to focus on the part that we know how to do, which is make vehicle platforms.”

The award was awarded through the National Advanced Mobility Consortium under other transaction authority, a route designed for prototypes and faster than a traditional FAR-based contract. Haag compared it to “like a prequalified carrier network,” where the government posts a requirement to a membership pool and participants respond with solution write-ups and a price proposal.

From a handful of prototypes to 5,000

The current order book is intentionally small. The program is in a low-volume prototype demonstrator phase, usually involving three to 10 units, before moving to low-rate initial production and eventually higher volumes.

Low-rate production is meant to test whether the vehicle can be built the same way more than once.

“We’re going to buy a hundred and not 5,000 to make sure that they all come out and do the same thing as we expect them to,” Harris said.

For now, the Army is buying information.

“This prototyping phase is typically about figuring out what you actually want. This is where the requirements are evolving, the approaches are evolving,” Harris said.

The approach reflects a broader shift: the Department of War gives industry a problem and asks what it already has that can solve it.

The next milestone is a National Training Center demonstration in six to 12 months, Horton said, after which the Army is expected to return with requirement changes. The contract also includes the potential for follow-on orders, according to the announcement. American Rheinmetall and Harbinger announced their partnership on May 27.

Cost is central to the strategy, and the bet is on commercial production.

“The real uniqueness of our offering is that it is foundationally a commercial vehicle,” Horton said. “So there are some things that are not fully militarized, but I think that allows a lower cost of entry for the Army to get these mass-produced.”

Haag said the demonstration stage will be critical.

“What we want to make sure we have is Soldier input into the platform, into the Graphical User Interface and how you interact with it,” Haag said. “Not just demos, but try to real-world use it as best you can so that it’s like, ‘Wow, this is the thing I’m looking for and it can do all these things and we’re 95% of the way so here’s the other 5%, let’s see if we can get it.’”