For the past four months, a fleet of self-driving white minivans has roamed the streets of Chandler, Arizona, picking up hundreds of paying riders. Like standard issue taxis, these cars pick up passengers and ferry them to a destination of their choosing. But unlike taxis or other rideshare services, a person isn’t doing the actual driving. This is Waymo One, and it’s asking us to do something we haven’t done before: Trust a driverless vehicle to deliver us safely from Point A to Point B. In smaller ways, we’ve already begun to shift responsibility to the AI-assisted devices in our lives. We rely on Google Maps to navigate through our days, ask our virtual assistants if it’s going to rain later, and have probably seen, if not driven, one of the many new cars equipped with partial self-driving features. But relinquishing full physical control to a non-sentient driver requires a new, heightened level of trust. “When I think back to my first ride, so much was running through my head,” says Waymo’s Ryan Powell. “What will it be like? What can the car really ‘see’? How does it ‘think’?” Powell leads UX research and design at the self-driving technology company (formerly part of Google, Waymo is now an Alphabet subsidiary), making it his job to think about how exactly these driverless cars can engender trust among riders. The car’s lidar (light detection and ranging), cameras, and sensors capture a mind-boggling amount of data on surrounding roads and traffic conditions, but the passenger doesn’t—and probably doesn’t want to—see everything the car sees. Instead, a series of interfaces translate that data into tidy visuals and updates for the rider that better match how we process the world, reassuring passengers that the car is making safe, sound decisions. Taken together, it’s a user journey that Powell says had to be built from scratch. “There’s no playbook for self-driving cars,” he says.We sat down with Powell ahead of his talk at SXSW to learn more about that from-scratch Waymo playbook, and all the nitty-gritty work that goes into designing technology that can earn—and keep—our trust on the road.