To do this, Waymo is teaching its software, which has become accustomed to driving cars, how to instead manage the increased challenge of a truck. It's done in the same way you'd teach anyone with passenger car driving experience how to drive a semi.

Waymo isn't the only company testing self-driving truck technology. Embark has teamed with Frigidaire and Ryder to deliver smart fridges; one of its trucks just completed a trip from California to Florida. Also, Uber announced just this week that its autonomous trucks have been operating in Arizona for a couple of months now. That's a result of Otto, the company that Uber acquired in 2016 and has been the center of a lawsuit between Waymo and Uber. The two companies settled recently and are now discussing a partnership.