Update, March 19: Starsky Robotics, one of the companies spotlighted in the "60 Minutes" report, has shut down. Read here to see why the company founder says the technology just isn't ready ... yet.

The CBS News show “60 Minutes” on Sunday night aired a segment on autonomous trucks. The report was startling not because of the topic but because it showed a truck navigating highways with no one in the cab. In this case, a picture (or video) is indeed worth a thousand words. Self-driving rigs are here.

This confirms what I’ve heard experts say at recent conferences. The big hurdle for self-driving vehicles is no longer technological. It’s regulatory. And, more specifically, it’s the challenge of gaining public acceptance of self-driving vehicles. There has been doubt that state and federal officials would permit large-scale operation of driverless trucks because people would oppose 80,000-pound rigs rolling down the road with only a computer at the controls. The turning point, some say, is when self-driving cars arrive. Once drivers trust the technology, they’ll be willing to have driverless trucks share the road with Grandma in her Buick or little Susie on the school bus. It’s not yet clear to me when we might cross that public acceptance threshold.

But the economics of autonomous trucking are very clear. Labor is a much larger cost for trucks than for railroads. So when you take the driver out of the equation, trucks leapfrog past railroads and gain a cost advantage. Take one person out of the locomotive cab, or even both, and the cost impact is not game-changing for railroads the way eliminating the driver is for trucks.

Now consider this: The primary reason shippers use railroads is because they are cheaper. No one uses railroads because of their service. Railroads are hard to deal with, carload shippers generally have to provide their own cars, and rail and intermodal service is slower, more complicated, and much less reliable than trucks. So if trucking costs plunge below that of railroads, look out. Intermodal is highly susceptible to highway diversion. Even bulk traffic, such as grain, is not immune.

Practically the lone advantage railroads enjoy is their privately funded infrastructure. They own their own rights of way, maintain them well, and can expand at will. Highways largely rely on federal funding and that means trying to get bills passed in an increasingly gridlocked Congress. The federal Highway Trust Fund has been in the red since the 1990s and there appears to be no way to build our way out of chronic highway congestion in urban areas on the East Coast, California, and Texas.

If railroads have an opportunity, it’s in their relatively congestion-free routes into and out of major markets. The other advantage railroads have from owning their infrastructure is automation is far easier to accomplish, and you can do it in one fell swoop by linking dispatching systems, positive train control, and locomotive control systems like Trip Optimizer and LEADER. Yes, a host of issues would need to be solved, from how you handle broken coupler knuckles to setting out a car that a wayside detector flagged.

Autonomous trucks could help railroads in one way: Dray moves to and from intermodal terminals. Combine that with fully automated terminals, and you lower your costs significantly. It’s also far greener than over-the-road trucks.

That is, unless trucks electrify. Battery-powered rigs, the Oliver Wyman consultant Rod Case told the RailTrends 2019 conference, are a bigger and more immediate threat to railroads than autonomous trucks. Electricity to charge truck batteries is getting cheaper and cheaper. Battery technology keeps improving. And the cost per mile is way below diesel trucks – and, of course, railroads. Electric trucks also do not have public acceptance issues or regulatory hurdles. Simply swap a diesel rig for an electric rig and you’re off to the races.

There are widely divergent views on how highways could handle the extra volume that’s currently moving on rails. Suppose, for the sake of argument, that all 14 million annual intermodal loads were suddenly diverted to highways. That’s a monumental traffic jam, right?

Well, it depends. On one side, an optimistic view sees self-driving cars and increased use of ride-sharing leading to less highway congestion, which would free up space for more trucks on the road. The pessimistic side sees highways being increasingly congested and rail continuing to play an important role regardless of advances in autonomous and battery technology. Simply put, there’d be no room for all the extra traffic.

I’m not smart enough to tell you which scenario may play out. But one thing is for sure: People are tripping over themselves to invest in the development of autonomous driving technology because the global market is so big. Consider that there are 275 million registered vehicles in the U.S. alone, while the Class I railroads roster fewer than 29,000 locomotives. Rail-related research and development spending is tiny by comparison to what Silicon Valley is investing in autonomous driving systems. And that’s not a good thing for railroads.

You can reach Bill Stephens at bybillstephens@gmail.com and follow him on Twitter @bybillstephens