In February, Senator Ed Markey (D-MA) sent letters to seven U.S. companies working on autonomous vehicle technology with a list of questions. He especially wanted to know how often these companies’ vehicles — operated by Aurora, May Mobility, Motional, Nuro, Tesla, Waymo, and Zoox — rely on input from remote staff. They all refused to say , according to the results of Markey’s investigation, which were released Tuesday. The information published by Markey’s office is the latest example of how