Waymo has only weeks to meet its self-imposed deadline to launch a public taxi service using fully automated cars by the end of 2018. And right now, that deadline looks tough for the company to meet.

The Information has learned that within the past month or so, due to concerns about safety, the Alphabet company put so-called “safety drivers” back behind the wheel of its most advanced prototypes, ending a year-long period in which those people generally sat in the passenger or back seat.

Meanwhile, The Information also has learned that Waymo is only testing its most advanced prototypes in about 60 square miles, or roughly 5% of the Phoenix metropolitan area, say people with knowledge of the situation. These cars have Waymo’s most stable and vetted software, and which are supposed to be the basis for the fully automated robotaxis. That previously unreported figure suggests that any service launched this year will be severely limited for some time.