Tesla CEO Elon Musk has called LiDAR technology a "fool's errand" that isn't a cost-effective way to make advanced driver assistance systems like Full Self-Driving (Supervised) safer. However, the National Highway Traffic Safety Administration (NHTSA) is escalating its investigation into FSD partly due to concerns that its camera-based system may not be adequate. The NHTSA has identified nine crashes where it believes Tesla FSD's degradation systems may not have been functioning properly. However there could be many more crashes that occurred in similar environments. Tesla has stated its FSD system has driven a cumulative total of 3.6 billion miles, triple what it reported a year ago.