“The National Transportation Safety Board (NTSB) appreciates the productive and professional cooperation extended by Tesla’s technical staff to our investigators over the course of our various crash and incident investigations, such as our recent work in [fatal crashes in] Spring, Texas, and Coral Gables, Florida,” she wrote. “I am deeply concerned, however, that Tesla’s action — or rather, inaction — to implement critical NTSB safety recommendations has not demonstrated the same productivity or professionalism.”