Although I really do welcome the development of autonomous vehicles, I can't help wondering why on earth we would want to haul a load of butter thousands of miles across a continent. It's not environmentally beneficial in any way - fossil fuel and greenhouse gases, air pollution, dust, noise and disturbance..... to be really clever, we'd only do this if it were absolutely necessary. And this isn't.

I completely agrre with CarolynFarstrider. Maybe that was only an experiment made with butter to test ALSO the fridge and the cold chain capabilities.

So where's the refrigeration equipment? Or can you only haul butter during the winter?

First reaction on reading the headline: What? They allowed a 20-ton load of butter to be shipped in a semi e-truck autonomously for 2800 miles? OK, so two personnel were on board, whew! Still, how long did it take? How many recharges were necessary? Was the refrigeration system connected to the batteries or did it have a generator? Was the rig able to do all this completely anonymously? Was this a commercial for Land 'O Lakes buttah? Take the train if you want efficiency.

If that box had been empty, someone would have complained about wasting all of that fuel to just prove the point that it could be done, right? And if it had been only half full/half empty, someone would have a gripe about that as well. So they loaded it up to near capacity weight wise to make as close to a real world test as possible. What is wrong with that?
The cheaper the transportation costs are, the lower the prices of the goods will be, plus, you don't have to worry about men and women making stupid decisions like how fast one can go, when to put the chains on, driving under the influence of foreign chemicals in their body, anger issues, etc ad infinitum.
These so-called "greenhouse gasses", in case people don't stop to think about this, we build greenhouses for a REASON!! It's because they are good for plants and help them to grow faster than they would out in free air. CO2 is either generated in them via yeast colonies or introducing the gas from tanks because the green plants inside use CO2 as a part of their metabolic process!! When people are very ill, they get put into an Oxygen tent or a mask is put over their nose so they can breathe pure Oxygen from a tank or Oxygen concentrator because it's good therapy for them! If someone can live off of everything that they grow on their own land and like wearing animal pelts or sack cloth, I'm totally fine with all of that. But please don't think that you can force me or shame me into doing it too.
The rig in the photos may not have been the one actually used for the test, or its reefer unit might be built into the box, not an add on. Who knows, maybe the compressor was driven off of a wheel or the truck engine? But that kind of thinking is a bit out of the box for most.

As there is a growing shortage of truck drivers, this will be in great demand.

Please see Presidential candidate Andrew Yang's website Yang2020.com for a LOT more information on what autonomous vehicles mean to the 10s of thousands of truck drivers who rely on this industry for their living. We're well into the Fourth Industrial Revolution and this achievement is only one of many changes that will gravely affect the workforce. That's why he's advocating for a Freedom Dividend paid for by taxing these technologies so that no one will be without a foundational income, no matter what tech they have to adapt to and how quickly. About half the nation's jobs, and not all of them blue collar, are in jeopardy within the next 10 years, many sooner.

If you drive for a living your days of gainful employment are seriously numbered. Followed closely by flying. Followed closely by repairing gasoline vehicles...

The article does not state that the truck was a BEV. This trip was done to test the autonomous capabilities of the driving technology package by Plus.ai. It is implied that a conventional class 8 tractor was retrofitted with the required equipment. Autonomous operation and BEV are 2 separate technologies that do not have to be fitted to the same vehicle for one or the other to work.

As the front of the trailer does not have a conventional refrigeration unit readily apparent, it may have been a bottom-mount unit hidden behind the aero fairings. Since butter has to remain only cold and not frozen, a smaller refer unit could be used.

The article clearly states that the trip took 3 days. Taking fuel/food stops into account and the time limits that drivers can log every day, 3 days seems like a reasonable time for a cross country journey.

The article clearly states "there was a safety driver and a safety engineer aboard at all times with the former taking over the controls as needed, as is required by law". The author alludes to the fact that laws are different in every state concerning autonomous vehicles. This would also be a test of the system to verify that it knows where it is and that when moving from one state to another, its behavior would comply with current laws.

Much can be learned when reading the entire article and not stopping at the headline, eh?

I think the butter was chosen in case there was an accident, the resulting mess wouldn't harm the environment.
What I wonder is how many people were involved with the trip. Usually, one driver is all that's required, but how many people did this take to be successful? I would bet at least half a dozen, and this is for one truck.
How well does this entire concept scale up to a fleet of trucks? Maybe I'm missing something, but I would think the trucking company will need to track every movement of these devices, if only for evidence to win in the inevitable lawsuits from accidents.