One scenario where autonomous driving could ultimately prove useful is in the long-haul trucking industry, where drivers routinely do 10-hour stints with legally required breaks in between. An autonomous truck wouldn’t have to stop to rest.

To put this into perspective, a startup named , which develops assisted driving systems for tractor trailers, recently sent a truck from Nogales, Arizona to Oklahoma City carrying watermelons. Those two points are just under 1,000 miles apart, but TuSimple routed the truck through Dallas to the south of Oklahoma City, making the trip closer to 1,200 miles.

The first 65 miles, from Nogales to Tucson, as well as the last 200 miles, from Dallas to Oklahoma City, were driven by a human. But the 950 miles between Tucson and Dallas “was done autonomously using TuSimple’s self-driving technology,” according to the company’s .

A human driver can complete the entire trip in 24 hours and six minutes, while TuSimple demonstrated its autonomous system can make this trip in 14 hours and six minutes, which is 42% faster.

Now, there are a few details to clarify here. For one, that 24-hour estimate factors in the time a truck driver would spend not driving. The Federal Motor Carrier Safety Administration mandates that a driver must spend 10 hours off duty after driving 11 hours within 14-hour period. Here’s how that’s written in the administration’s :

You are allowed a period of 14 consecutive hours in which to drive up to 11 hours after being off duty for 10 or more consecutive hours. The 14-consecutive-hour driving window begins when you start any kind of work. Once you have reached the end of this 14-consecutive-hour period, you cannot drive again until you have been off duty for another 10 consecutive hours, or the equivalent of at least 10 consecutive hours off duty

It’s clear the 10-hour difference between the times TuSimple notes is all down to removing that break. But even then, the language in the press release is a bit vague.

TuSimple says the autonomous system can make “this trip” in 14 hours and 6 minutes, after saying it would take a human 24 hours and 6 minutes to “complete the entire trip” with stops. However, the entire trip isn’t 14 hours — that’s just the , mostly on I-10 and I-20.

If we put the route the truck may have run into , from Nogales to Oklahoma City by way of Tucson and Dallas, the estimated time is 17 hours and 47 minutes to cover 1,219 miles.

Bearing all that in mind, the takeaway here is that a long-haul truck with autonomous driving capabilities can complete what would be a 24-hour journey over 950 miles, as required by law, in 14 hours. That is impressive, and it’s easy to recognize the implications of shipping times effectively halved for those kinds of trips. But the press release doesn’t say how many times driver intervention was required during that 14-hour autonomous span. And if a driver must remain alert and on call, ready to takeover the wheel at a moment’s notice in a , that’s not really time spent off duty, is it?

Clearly, existing laws will have to be revisited and modified as long-haul trucking becomes increasingly autonomous. With that, many have understandably expressed concerns over truckers’ job security, though it’s important to remember that complete, Level 5 autonomous driving is so far off that drivers are still certainly going to be needed in the cab for the foreseeable future — especially because alone.

Trials like this one involving a precious cargo of melons are important milestones on the way to realizing , but they’re also a reminder that the industry is going to have to answer many questions before it gets there.