reporter: cruise says its mission is to work with cities and make it safer. there s over 40,000 fatalities happening on the roads in the united states. we have driven over 3 million driverless miles. and we have had no life-threatening injuries or fatalities. need to buckle is the same as always. reporter: waymo declined an interview with cnn and said it s proud of its driving record and creates better performance than a reference model of a human driver. avs aren t just in san francisco. cruise is already operating in austin, texas, and los angeles, too. chief nickelson has a warning for other cities. pay attention. get on board. get ahead of this. because it s coming your way. and i don t want them to have happen to them what has happened