The autonomous cars can be summoned by users just like any other Lyft ride, using the Lyft mobile app. Aptiv did specifically note that these cars are just going between popular locations, though, so don't expect to be picked up by one at your house. This is similar to the way the CES rides worked.
Also, if you don't want to subject yourself to autonomous testing, you don't have to. The program is opt-in, so if you demand a human in the driver's seat, that human will be there. But Aptiv does brag that after 400 rides during CES, the autonomous cars scored a 4.99 out of 5 stars in Lyft reviews. We imagine the one dissenting review was something like, "Driver didn't talk to me the whole way 0/5 won't ride again."
The autonomous Bimmers are roaming right, now, too. The companies launched the program on May 3. So, that's good news for any of our intrigued readers looking at this while leaving the Vegas airport.