The 40% number isn't very informative. The report has multiple notes about it: ODI analyzed data from crashes of Tesla Model S and Model X vehicles involving airbag deployments that occurred while operating in, or within 15 seconds of transitioning from, Autopilot mode. Some crashes involved impacts from other vehicles striking the Tesla from various directions with little to no warning to the Tesla driver. ODI analy…
Even if the only benefit of Tesla's autosteer is that it makes you more focused in the parts that are actually dangerous, a 40% improvement is still a 40% improvement.