PITTSBURGH — An hour before dawn Wednesday, Uber hit the green light on a project that many here have seen, but never experienced. Until now.

Some of Uber’s heaviest users woke up to an email Wednesday inviting them to test out the company’s new self-driving cars, the centerpiece of a fully autonomous fleet that Uber plans to use in the long run to replace human drivers. The pilot project, which is the first in the United States to include members of the public, offers a taste of a technological future thousands have only read about.

Do these cars really work? Judging by an early demo that Uber provided to reporters this week, the answer is yes – at least under ideal conditions.

In some ways, Uber’s self-driving car works better than Google’s. Having now tested out both, I can say firsthand that Uber’s car is better at accelerating and braking like a real human being.

This Uber program is only a test; its riders, guinea pigs. Still, when Uber invited me to try the vehicle earlier this week – momentarily even putting me behind the wheel to operate one – mishaps were few and far between. In a word, things felt normal. Mundane, even.

Our route took us through Pittsburgh’s Strip District, over a bridge or two, across some faster stretches of highway, back onto slower side streets and finally across some train tracks. It was a dry, sunny day, however, and we didn’t climb any of the city’s big hills or drive on any poorly marked streets. Sitting in the front seats were a pair of Uber “safety drivers,” full-time employees whose sole job is to test what the company’s engineers have produced.

Uber declined to say how many invites went out Wednesday. But it is offering the feature to those with the most Uber trips under their belts. Those customers will have the option to accept the rides, which will be free for now, or they can ignore the program. Those who join will receive an update to their Uber apps that will let them summon a driverless car via UberX.

In order to hail one, the ride’s origin and destination must be within the operating boundaries that Uber has set out for its robotic vehicles. Currently, the cars work in downtown Pittsburgh, across the Allegheny River in the North Shore neighborhood, and eastward past Carnegie Mellon University toward Shadyside.

Once inside the car, users will be greeted by a tablet displaying information about the ride they’re about to take.

When the ride begins, the tablet switches to display information such as the vehicle’s speed, its route, and what the sensors can see around it. In a bit of a gimmick, passengers can also tap a button to take a selfie.

As for the vehicle’s interior, a series of lit icons above the dashboard told us what mode the car was in. A blue circle meant the car was under manual control. A single green light with a check mark meant the car was ready for autonomous mode. And when both the green light and a white light with an arrow were illuminated, it meant that the autonomous mode was engaged.

To start the autonomous mode, the safety driver behind the wheel pushed a small silver button on the console near the parking brake. From that point on, the car was in control: It eased toward stop signs and came to a full stop. It accelerated out of them very gently. It followed other drivers at a respectful, generous distance, and obeyed the posted speed limit at all times, even when a human driver might have gunned it a little.

At one point, the vehicle came upon some pedestrians crossing the street. It seemed for a moment as though the car might plow through them, but the driver took over before any automatic braking features could kick in. The safety driver also took control at several moments during the trip to make, for example, a left turn across traffic and onto a bridge on-ramp. Company executives told me later that Uber will be very conservative about letting the software run on its own, at least at first. As users grow accustomed to the technology, Uber will probably relax somewhat and give the computer more leeway.

.Uber is working on a number of self-driving vehicles. One is a Ford Fusion sedan that’s been modified using aftermarket parts, which explains the bulky camera assemblage on its roof. Another is a Volvo SUV. Uber’s direct partnership with the carmaker means that the Volvo will bear a thinner, sleeker sensor package.

Uber executives hinted Monday they were working on a third model of self-driving car that wasn’t ready for display.

“We think of this as the desktop computer,” said Eric Meyhofer, Uber’s lead engineer at the Pittsburgh facility, gesturing to the Ford. “And this” – he turned to the Volvo – “as the laptop computer. The next time you’re here, we’ll show you the smartphone.”

After riding in the back, it was time for a ride in the front. I unstrapped myself from a set of thick seat belts with embedded airbags and swapped places with the safety driver. Public passengers won’t get to do this, but taking the wheel helped shed light on the safety driver’s role and what it feels like to do his or her job.

Even with my fingers lightly on the wheel, it was apparent that the car was making many tiny course corrections during the trip. Each modified Ford is equipped with seven laser sensors, radar that can see in 360 degrees and 20 optical cameras that are mounted everywhere. You can even find some beneath the side-view mirrors. All this equipment helps the car build a three-dimensional map, gathering more than 1.4 million data points every second about the world.

This real-time map is constantly being matched against a map that’s been pre-loaded into the car’s brain. Uber collects the new, real-time data from its cars twice a day, and it pushes updated maps to its cars once a week. The maps are not only stored locally on the cars themselves, but also in the cloud, where the vehicles can access updates using an over-the-air wireless connection such as WiFi or 4G LTE. (That marks a notable difference from Google’s driverless car, which is kept disconnected from the Internet as a safeguard against hackers.)

For turn-by-turn navigation, Uber’s driverless cars use the company’s own proprietary system, not Google Maps or another third party as riders may be accustomed to seeing in typical Uber rides today. To help with the GPS accuracy problems that can frustrate riders and drivers currently, extra hardware from the GPS technology company Garmin has been installed on the Ford Fusions. I’m told this will improve the GPS experience over what we see with smartphones, but the company lacks detailed information on just how much better it will be.

Uber has yet to see how its vehicles fare in slippery winter conditions, where humans may be even more hard-pressed to relinquish control (or their perception of it) to computer code. Still, the technology as it stands feels pretty solid. Early adopters: Prepare yourself to be thrilled and bored, all at the same time.