Dave Mercer has been driving trucks across America since 1986. He has hauled ice cream to Nevada, burgers to Oregon, and trailers to Baltimore.

“It can be a rough life,” he says. “You’re away from your family a lot, and raising your kids from the road is a hard life. I’ve talked to a lot of principals on the phone. But it also provided me a good lifestyle. I drove through all the recessions and depressions and don’t recall ever slowing down.”

Three and a half million miles — and one divorce — down the road, Mercer was ready for a change of pace. In 2015, he joined Peloton Technology, a Californian startup developing self-driving trucks using robotics and artificial intelligence. Mercer helps test that technology on tracks and public roads, preparing for the day when truckers might leave their cabs for good.

“We can’t play stupid to the fact that down the road there’s probably going to be a fully automated truck running up and down the highway,” Mercer says.

Head to the California Department of Motor Vehicles (DMV) website and you can read reports of every collision involving the cars enrolled in its autonomous vehicle test program. They are a litany of mundanity. On March 29, a scooter bumped into one of GM Cruise’s self-driving Bolt cars and damaged its left-side wing mirror. Two days earlier, a BMW SUV clipped another Bolt while changing lanes. The big excitement on March 24 was that two of GM’s cars were rear-ended on the same day, resulting in some minor scratches and dents.

What you probably won’t have heard about is the first-ever crash involving a self-driving truck, which occurred last November on California’s Junipero Serra Freeway in Silicon Valley. At 9:45 in the morning of November 9, a semitruck owned by startup Starsky Robotics was involved in a collision with a passenger car. The car hit the truck’s tires and broke a mud flap and had to be towed from the scene. There were no injuries.

This collision only came to light because the California Highway Patrol reported the crash to the U.S. Department of Transportation (DOT), as it must for any incident involving a commercial motor vehicle. Because California does not currently have a testing program for self-driving trucks, developers do not have to file reports on failures and crashes. (Nor are they permitted to test advanced driverless technologies. Starsky did not confirm whether any of its self-driving systems were engaged at the time of the collision.)

Other states are even less restrictive. Arizona and Florida welcome self-driving trucks without any special permits or reporting; in February, one of Starsky’s big rigs drove a seven-mile test run near the Everglades without a human in the vehicle at all. One of its rivals, Embark, completed a coast-to-coast run from Jacksonville, Florida, to Los Angeles in an automated truck the same month.

Unlike the high-profile urban and suburban tests of autonomous passenger cars conducted by Waymo, Uber, and GM Cruise, driverless truck developers have been quietly carrying out their experiments on highways across the Sunbelt. According to figures submitted to the DOT, automated trucks racked up well over 200,000 miles on public roads last year.

A truly driverless truck would change the face of trucking. In a cutthroat industry operating on razor-thin margins, drivers’ wages and benefits are the largest cost, accounting for nearly half of a carrier’s cost per mile. The first company that can eliminate drivers could undercut its rivals and dominate the market.

Automated trucks might also reduce the nearly 4,000 fatalities from large truck crashes that occur each year in the United States, some of which are known to result from driver fatigue. There is even a potential environmental benefit, as smart driving systems reduce fuel use and smooth the transition to alternative fuels and electric vehicles.

But none of this is guaranteed. Cheaper freight transport could stoke demand, wiping out any carbon savings and increasing congestion. Millions of well-paying blue-collar trucking jobs could disappear, and the safety benefits have yet to be proven. Driverless trucks may simply replace today’s human errors with higher-tech mistakes — and an out-of-control 18-wheeler could cause many more fatalities than the failure of Uber’s self-driving car in Tempe, Arizona, in March that resulted in the death of pedestrian Elaine Herzberg.

Automated trucks have only just started to roll, and their final destination is anything but clear.

Trucking is the original internet of things, a $700 billion juggernaut that moves 70 percent of all goods in America and employs millions of drivers, mechanics, loaders, and managers. But it is also a deeply conservative industry, dominated by a few slow-moving incumbents and a long tail of tiny mom-and-pop businesses, using technologies and business models that have remained largely unchanged for decades.

Engineer Josh Switkes was one of the first to realize that trucking was ripe for Silicon Valley’s brand of high-tech disruption. “I got excited about automated trucking 10 years ago for the same reasons people are getting excited about it today,” he says. “It’s a huge industry with very concentrated expenses in fuel, in crashes, and in labor. You have big enterprise customers where you can deploy broadly quite quickly and make huge economic benefits.”

In 2011, Switkes launched Peloton, the startup Dave Mercer now drives for. “At that time, Google had just announced their self-driving car project, but most people saw vehicle automation as something pretty far off in the future,” Switkes says.

Instead of trying to build a complete self-driving truck, Switkes would focus on a technology called platooning. Tour de France cyclists harness the aerodynamic efficiencies of riding in tight packs to travel much faster than they could individually. In the same way, Peloton’s trucks would tailgate each other at a distance of just 50 feet, using a combination of radar, video cameras, and short-range radio messages to automatically synchronize braking and acceleration.

“A midsized truck fleet will spend hundreds of millions of dollars a year on fuel,” Switkes says. “If we can save even a few percentage points of that, it will make a big difference to their bottom line.”

Peloton’s system is likely to go into service this year with several large haulage companies, but it won’t change much about the way truckers or companies operate. Both drivers in a platoon still need to steer and pay constant attention to the road, and the system only operates on highways that have been mapped by Peloton and that aren’t experiencing severe weather or traffic jams.

“It’s not going to be a different job with platooning,” Mercer says. “When I used to drive cross-country, we were running pretty close, but we didn’t have the technology to really keep it safe. This technology adds that safety factor.”

Mercer is excited about the new technology, but he’s skeptical that it will replace human drivers anytime soon. “We’re fooling ourselves if we think we can throw a fully automated truck out there on the highway at this point in time and have the public accept it,” he says. “I wouldn’t want to see it. I wouldn’t want to pull up beside a truck myself and see no driver in there.”