A little more than a year ago, self-driving software company Aptiv and Lyft launched a pilot project to test a robotaxi service — with human safety drivers still behind the wheel — in Las Vegas during the week of CES.

That one-week pilot never ended. And now, the companies say they’ve given more than 50,000 rides in Aptiv’s self-driving BMW 5 series vehicles via the Lyft app. The average ride received a rating of 4.97 out of 5 stars, according to Lyft, which added that 92% of riders said they felt very safe or extremely safe during the ride.

The milestone illustrates how far Aptiv and Lyft has come in a span of 18 months. It also shows that in spite of amassing so many rides, there’s much left to achieve before humans leave the driver’s seat for good.

Lyft and Aptiv first launched the pilot in January 2018. By August, they had surpassed 5,000 self-driving rides. Aptiv’s investment in Las Vegas expanded as those ridership numbers grew. The company opened a 130,000-square-foot technical center in the city to house its fleet of autonomous vehicles as well as an engineering team dedicated to research and development of software and hardware systems, validation and mapping.

However, this is not a pure robotaxi business, yet. The autonomous vehicles still have safety drivers behind the wheel. And the rides are mostly — but not completely — done in autonomous mode. The cars are required to be in manual mode in parking lots and hotel pick up areas, according to Lyft.

The Lyft-Aptiv program will continue indefinitely, according to Lyft. It could even expand. The ride-hailing said it anticipates “working together to continue to bring self-driving technology to new cities and passengers.”