According to the National Highway Traffic Safety Administration (NHTSA), Tesla's Autopilot-enhanced vehicles crash 40 percent less often than cars without driver-assistance technology. The agency recently released a new report [PDF], spotted by IEEE Spectrum.

The report was conducted in response to a fatal accident in June 2016, when a tractor trailer crashed into a Tesla Model S on a Florida highway, killing the Tesla driver, who was using Autopilot at the time. The NHTSA then opened an investigation into the incident, which was the first fatality involving Autopilot.

Tesla’s Autopilot has sensors that can engage the car’s brakes when it detects an oncoming crash, even if the driver doesn’t react in time, as well as cruise control that takes the speed of other cars into account. (Autopilot also has automatic lane changing and automatic parking capabilities.) In this case, the Automatic Emergency Braking part of the system didn’t deploy or warn the driver before the collision. However, the report notes that the cars' automatic braking is only designed for rear-end collisions—which means it can't be blamed for a side collision. Those kind of crashes are beyond the scope of the system, according to the report, which means it wasn’t a question of the technology malfunctioning.

In the case of the fatal accident in Florida, the NHTSA report found that the Tesla driver was apparently distracted for at least seven seconds, and never tried to brake or steer away from the truck.

NHSTA

 
In fact, the report found that not only was Autopilot not to blame for the 2016 crash, its related Autosteer technology was actually responsible for a significant reduction in Tesla crashes. The Autosteer system can detect road markings and the presence of other vehicles to help drivers stay within their lane, but there's a catch: The driver is required to keep their hands on the wheel. If the sensors don’t detect hands on the wheel, the software warns the driver several times before turning the technology off.

Once Tesla debuted Autosteer, crash rates for its vehicles went down by almost 40 percent. For every million miles driven before Autosteer, there were 1.3 crashes where the Tesla’s airbags were deployed; after Autosteer, there were only 0.8.

All Tesla cars now come with the hardware necessary to drive fully autonomously, but the law still says drivers can’t let the car take the wheel entirely. In the meantime, while it's clear that Tesla could improve upon its current driver-assistance tech, the report shows that machines are capable of driving more safely than humans—in certain situations, at least.

[h/t IEEE Spectrum]