A Waymo autonomous vehicle travels on Steiner Street in San Francisco, on Nov. 17, 2023. Jason Henry/AFP via Getty ImagesThe country’s main transportation safety agency is digging into the behavior of Waymo’s autonomous vehicles. Meanwhile, in San Francisco, the complaints about the cars continue to stack up.The National Highway Traffic Safety Administration said Monday that it has opened an investigation into the company’s newest autonomous driving model and its ability to respond to traffic si...