OLYMPIA, Wash. (AP) – Only on sidewalks and crosswalks, only with human oversight, and always with functioning brakes – those are some of the new rules for personal delivery robots in Washington state.

Gov. Jay Inslee signed a bill imposing those rules and others Tuesday, setting out a framework for a new technology that is growing in popularity, after lawmakers wrestled with whether they should be treated as automobiles, pedestrians, or something else entirely.

Companies including Amazon have rolled out robot delivery programs. The online retail giant began testing cooler-sized six-wheeled robots in Snohomish County, Wash., just north of Seattle, before lawmakers had passed the state’s rules.

The bill also requires identification numbers, liability insurance, accident reporting, and lights for night operation. One company, which worked with the bill’s Washington sponsor, said that their devices are typically overseen by humans who monitor several at a time.