Robot, Take the Wheel. Jason Torchinsky

addition to propelling itself, the cart had a mechanism by which it could be made to turn at preset points on its journey, by placing wooden blocks at locations between gears (some sources describe placing pegs into holes). It seems that only right turns were permitted, but even with that limitation the end result is impressive: this was a programmable machine, capable of executing a stored set of instructions for a very short journey. That, at least in a very simple sense, is an autonomous vehicle.

      Da Vinci never actually produced his cart, but a replica based on his original drawings was built in 2004 by Paolo Galluzzi, director of the Institute and Museum of the History of Science in Florence.2

      1830s–1840s: Railroads

      There was a pretty significant gap between when da Vinci conceived the cart and when it was produced, which isn’t really shocking, since da Vinci’s cart was never actually built and, even if it had been, as a fifteenth century Big Trak, it likely wouldn’t have had much practical use. This, however, isn’t to say that technological development in the automotive arenas wasn’t moving ahead; it was, and pretty significantly.

      The advent of steam power was, of course, hugely significant in the development of the automobile. Nicolas-Joseph Cugnot had built the first full-size, working automobile in 1769, but since it was incredibly cumbersome and slow, it was doomed to wreck pretty quickly. Developments soon after led Cugnot to create increasingly practical steam-powered automobiles, with purpose-built cars like Trevithick’s London Steam Carriage of 1801. He later made others to meet the eventual boom in steam omnibuses in England in the 1830s.

      But with the boom came difficulties with powerful horse lobbies that were not willing to lose business to some filthy mechanical upstarts, and this, coupled with generally poor road conditions, forced the early automobile builders to abandon the shoddy network of roads. Instead they laid a network of ideal pathways for their automobiles to traverse. These pathways were extremely low rolling resistance roads, allowing the crude vehicles to carry vast amounts of cargo and passengers; by building a set path for these automobiles, the need to develop steering systems was effectively eliminated, with the pathway handling the steering and navigation through its direction and shape.

      We call these pathways “railroads” or “trains.”

      In many ways, we can think of railroads as one of the earliest semiautonomous vehicle systems, and perhaps to this day still the most common and vast network. A train is an automobile, fundamentally—a self-propelled vehicle, just like the car you drive to the Dairy Queen to do your nightly burnouts in.

      There are two major differences between a train and a car: scale and automation. A train is huge compared to a car. Trains, as the earliest automobiles produced in real quantities or really used by the general public, compensated for the crude state of the art by requiring fewer complex mechanisms (the locomotives) and maximizing their use by having them pull long trains of passenger and cargo cars. That’s how money was made—locomotives were not going to be the sorts of vehicles sold to every Thomas, Dickomas, or Harryomas in London.

      Trains also differ from automobiles, as we understand them today, in that they have one less dimension of operator control than a car. A car’s driver can control the speed of the car via the accelerator and brake, and the direction of travel via the steering system. In trains, the operator can also control the speed via the throttle and brake, but directional control is ceded to the machine; in this case, the railroad itself, and its associated switching hardware.

      In this sense a train is semiautonomous; an operator is required to control the speed and decide when to stop, but steering is autonomous. This sort of autonomy does not require any processing or understanding of the world on the part of the vehicle itself; the network the vehicle operates within handles that. A railroad is like a vast machine unto itself, with the ability to control multiple vehicles via increasingly complex switching and related hardware. These systems, in some form, were in place even by the mid-1800s.

      Railroads were humanity’s first successful deployment of a semiautonomous vehicle, and it remains a staggering success.

      1866: Whitehead Torpedo

      It’s not surprising that war provided the impetus to develop the first semiautonomous vehicle capable of reacting to its environment. I guess it’s a little disappointing, but, come on, we know the story; nothing spurs humans on quite as well as figuring out new and exciting ways to blow one another up. I’m not even going to pretend to moralize here, because we all know this is true.

      This first vehicle capable of sensing and reacting to its environment wasn’t a land vehicle, and it couldn’t carry people, just cargo, and that cargo was limited to explosives designed to blow up boats. The vehicle I’m talking about is a torpedo. Back when these were first developed, they were even called “automobile torpedoes.”3 The formal name was the Whitehead Torpedo, a name that sounds like some awful skin-care tool sold in the late 1980s on late-night television. While the basic idea was conceived by others, it was English engineer Robert Whitehead who eventually perfected the design and put it into production. Initially, the torpedo (named for the fish/ray that likes to shock its prey) was just a little unmanned boat that could be launched along the surface of the water to hit an enemy boat, detonate, and—hopefully for the launcher—sink the enemy boat.

      Whitehead added some crucial innovations to the torpedo, and those innovations are what made it the first environment-­reactive vehicle: it could keep to a constant, set depth under the surface and it could stay on a fixed course toward its target. Together, these were the makings of the first, crude guidance system, and the first time any inanimate object could really control its direction and compensate to maintain it, even with environmental inputs acting upon it.

      To do this, Whitehead installed two pieces of equipment in the torpedo: a horizontal rudder controlled by pendulum balance (to maintain depth) and a hydrostatic valve (a one-way, pressure-­relieving valve), and a gyroscope system driving a vertical rudder to keep it on course. These systems allowed the torpedo to control its path on two dimensions, with the third (forward travel) dimension provided by a three-cylinder radial-compressed air engine.

      The pendulum-and-hydrostat control of depth is ingenious. A hydrostat senses the depth, but does not control the horizontal rudder directly; if it did the torpedo would oscillate around the desired depth without ever really settling. The pendulum swings based on the pitch of the torpedo, and is connected to the rudder control in such a way that it can dampen the oscillations, providing much steadier control over the depth of the torpedo. The pendulum-and-hydrostat device was such a big deal at the time that it was called the “Whitehead Secret,”4 and the same fundamental design was used all the way up to World War II.

      The gyroscopic control for azimuth/yaw control came in 1895—prior to that, the azimuth (you know, direction, basically) was set with vanes by hand. The gyroscope in the Whitehead torpedo was spun up via a spring, and acted on the vertical rudder via gimbals. This kept the torpedo on a straight, direct path regardless of whatever forces (such as ocean currents) were acting upon it.

      1925: Houdina American Wonder

      The first conventional automobile to be driven without a person at the wheel was developed in 1925, but it’s really sort of a cheat. It wasn’t an autonomous car, but rather a remotely controlled car, so it was still driven by a human even though the human wasn’t inside the car.

      Pictures of the car show it labeled as a “1926 Chandler,” which is sort of confusing, since it appears to have been demonstrated and in operation since 1925. The car, nicknamed the “American Wonder,” was built by an electrical engineer named Francis P. Houdina.

      The way it worked was pretty straightforward: the car had a kite-shaped receiving antenna mounted on the tonneau, and electric motors under radio control to actuate the controls. It’s not entirely clear how many of the car’s controls were controlled by the motors or how