For a quarter century, the 1.86-kilometer road that runs uphill to the Goodwood Estate in West Sussex, England, has hosted the annual Festival of Speed. Each July, hundreds of modern and classic cars — some supremely rare and many of them worth millions — parade up the hill in a celebration of the things that people have loved about cars for the last century: style, speed, and the reverie of driving. As one person recently described it to me, it’s a show about “all the greatest hits in the story of the automobile.”

But in recent years, the Goodwood Festival of Speed has started to look toward the future. And there was no greater sign of that when, at this year’s 25th anniversary festival, two self-driving cars made it up the hill for the first time.

One was the slick, Hollywood designer-styled Robocar, which was created by Roborace, the British startup behind the fledgling driverless-racing-series-turned-AI-competition of the same name. The other was from industrial conglomerate Siemens, which partnered with the UK’s Cranfield University to retrofit a 1965 Ford Mustang with autonomous technology.

The two cars were as different in their looks as they were in their approaches — and their results. Over the course of the four-day Festival of Speed weekend, the Siemens car made just a few slow — and sometimes sketchy — runs, which generated headlines that were more about its shortcomings than its accomplishments.

Meanwhile, the Robocar and its four 135kW electric motors eventually whirred up the hill in about 1 minute and 16 seconds. That’s far off the typical 40- to 50-second pace of the fastest human-driven racecars that climb the hill every year, but it’s wholly respectable considering the company limited the robot car’s speed to about 75 miles per hour.

The Roborace team made that choice because it simply didn’t want any nasty surprises, Bryn Balcombe, the company’s chief strategy officer, told The Verge.

“The whole intent of this event is to build public trust in the technology, and getting it a clean run from the bottom to the top of the hill was the main objective,” Balcombe said. Put another way, Roborace didn’t want to crash and wind up in the news for all the wrong reasons.

Making sure that didn’t happen was a stressful process, Balcombe says, and it involved months of preparation. While Roborace has spent the last few years cutting its teeth with demonstration runs at Formula E races, Goodwood’s crowd of about 55,000 per day was a bigger crowd than the team was used to performing in front of.

“In terms of public exposure, in terms of the pressure that that creates, it was a lot higher than we’ve experienced before.”

“In terms of public exposure, in terms of the pressure that that creates, it was a lot higher than we’ve experienced before,” Balcombe said.

To get ready for Goodwood, Roborace employees made multiple visits to the Goodwood estate in the months leading up to the event. They used the company’s “DevBot” vehicle (which can operate autonomously or be driven by a human) to capture camera and LIDAR data, which they used to build a virtual map of the track.

They also had to work around the Goodwood Estate’s quirks. The team laid down markers where, during the event, hay bales would be placed on the road’s edges to soften any impact with the stone walls. They had to teach the car’s AI brain how to distinguish the road surface from the surrounding grass and dirt since there are no painted lines like you’d find on a highway. And the Roborace team decided to make its runs without using any GPS data, out of fear that the centuries-old cedar trees that line the road would block the car’s view of the navigational satellites that circle in space.

“As a car fan, your brain is melting at Goodwood. And yet we stood out from that.”

Roborace had to skip an appearance at the season 4 finale of Formula E in New York City. But it was all worth it, according to both Balcombe and Rod Chong, Roborace’s deputy CEO, because of how warmly the Goodwood crowd embraced the Robocar.

“The audience had a visceral response to it. They were clapping, which is incredible because if you look at the different types of machines that are going up the hill, it’s everyone’s childhood dream going up there, [with] all the old F1 cars and sports cars,” Chong told The Verge. “As a car fan, your brain is melting at Goodwood. And yet, we stood out from that. We were there as the vision of the future.”

“Every time we got to the top and crossed over the finish line, we got a round of applause from the audience, which is amazing,” Balcombe said. “It’s exactly the type of reaction that we love. And it’s amazing that people are cheering for the robot.”

The Robocar’s speed was sufficient, and its aim was true. So it’s not surprising that the fans were appreciative. The cheers weren’t as resounding for the robotic car Siemens brought to this year’s Festival of Speed, though. The retrofitted ‘65 Mustang wobbled as its V8 engine slowly rumbled up the hill. At one point, the car even nosed into the hay bale barriers. In comparison to the Robocar’s polished performance, there was no hiding that the tech-tweaked Mustang was very much the result of a university project.

“It’s amazing that people are cheering for the robot.”

Siemens followed a similar process in the run-up to the festival as far as data collection goes, according to Lee Dryden, the company’s head of business partnering and strategy and the man who cooked up the idea from the conglomerate’s side. But a major reason why the two autonomous runs were so different boiled down to a simple technical choice. Unlike Roborace, which opted against using GPS and inertial unit measurements for its runs, Siemens and Cranfield University relied exclusively on those technologies. The car was also programmed to swerve a little to show that the wheel was moving on its own, according to The Sunday Times. The result was that the driver of the Siemens Mustang had to repeatedly course-correct during every run.

Dryden said the team was “cautious” about relying on GPS but ultimately decided it would be enough. And he’s proud of what Siemens and Cranfield were able to accomplish, too, considering it ran into some mechanical trouble. “This is an actual authentic classic car that is almost original in every way,” he said about the Mustang, which he adds was chosen because the Duke of Richmond (who runs Goodwood) is a fan of American muscle cars. “I’m sure every Mustang owner would testify, keeping a classic car running is a hobby in itself.”

He also said he’s happy that Siemens and Cranfield were able to show off a totally different approach to the fully autonomous Robocar. “One thing we were also trying to acknowledge is that people love driving, and people love the sound of engines, especially at Goodwood,” he said. “So you don’t want to lose that, and our car can do both. You can drive it manually, you can enjoy what a V8 in a Mustang feels like, but then you can flip a switch and go up the hill autonomously.”

And despite the Mustang’s stilted runs, Dryden says the fans at the Festival of Speed didn’t turn up their noses. “The queues around the car when it was parked in the paddock were extraordinary,” he said. “It’s thought-provoking. We got a lot of fans coming up to us really sort of scratching their heads and asking a lot of questions.”

While it’s easy to compare and contrast Roborace and Siemens’ results, Dryden said he took a “more the merrier” view of the fact that these two cars showed up to this year’s festival. And he thinks Siemens’ approach hewed a bit closer to the current state of autonomous technology. “This is kind of how the world is at the moment. You’ve got existing technologies, which are a little bit analog, and look what happens when you apply something digital to it. You bring new life to it. You unlock its potential,” he said.

Dryden also notes that there are “lots of challenges to make completely autonomous vehicles. But to flip between autonomous mode and manual mode, I think that’s becoming a reality sooner than we think.”

Much like the current state of autonomous cars, it’s not entirely clear what comes next. “What does the future lie for our autonomous Mustang? You know, we’re fascinated to explore what that might be,” Dryden said. “We were not trying to create a new breed of car. This was just a celebratory moment, a fantastic sort of symbol of ingenuity.”

As for Roborace, the company will now turn its attention back to what it originally set out to do when it arrived on the scene in 2015: design a robot racecar competition that people will want to watch. The scale of that ambition has certainly changed since then. Instead of assembling a 20-car field, like a more traditional racing series, Roborace is now focused on pitting two teams of developers (likely from universities), each armed with a car, against each other in a track setting.

To spice it up, each team also gets paired with a famous driver, perhaps a celebrity with some experience behind the wheel or a real racing pro. The humans will race each other for a set amount of time, and then the teams will load their AI code into the cars and let the algorithms do battle. The company trialed a version of this in front of the crowd at the Formula E race earlier this year in Berlin, and it says it’s happy with the results, even if it’s a far cry from the idea of 20 robotic cars fighting for space on a racetrack (which, to be fair, was an idea that has obvious challenges since the beginning).

Roborace’s impressive Goodwood run has already inspired questions about whether the company will send the car to attempt other famous laps, like the Nordschleife course at the Nürburgring or up the treacherous Pikes Peak. But Chong said the company is focused on the competition. It is, after all, a startup with limited resources.

“It shows that we can create some waves with this crazy futurist project.”

“We could spend months mapping Nürburgring and running simulations and preparing the batteries so that they can output for that period of time, et cetera. It’s a big engineering project. But for us, the main priority is the 2019 championship launch,” he said.

Competition, he said, can help push the technology forward while also building confidence in the idea of self-driving cars, just like racing did in the earliest days of the auto industry.

“Goodwood helped show our concept works,” he said. “If you Google Robocar and Goodwood, and you see the amount of stuff there, it shows that we can create some waves with this crazy futurist project in this space. And it doesn’t always have to be ‘this car ran into that thing’ or ‘this horrible thing happened as they were testing in public.’”