This post has been updated since it was originally published to reflect that the Tesla Model S in the test was running an older version of Autopilot than the Tesla Model 3.
The Insurance Institute for Highway Safety tested five advanced driver assistance systems and reported that the Tesla Model 3 experienced the fewest incidents of crossing over a lane line, touching a lane line, or disengaging. The 2018 Model 3 also stayed within its lane more often than the four other vehicles in the test: 2017 BMW 5 series with "Drive Assistant Plus", 2017 Mercedes-Benz E-Class with "Drive Pilot", 2018 Volvo S90 with "Pilot Assist", and a 2016 Tesla Model S running an older version of Autopilot.
The results appear in the IIHS special issue on autonomous vehicles.
Across a set of 36 tests run on both hills and curves, the Model 3 drove outside of its lane only once, while the E-Class drove outside of its lane 12 times, the Model S 14 times, the S90 18 times, and the 5 series 33 times.
The difference in performance between the Tesla Model 3 and the Model S is particularly striking, as the Model 3 performed significantly better than the Model S, even though both models come from the same manufacturer. In fact, the Model S costs approximately 50% more than the Model 3, even though the Model 3 performed better on the IIHS tests. A key difference, however, is that the Model 3 was running version 8.1 of Tesla's Autopilot software, whereas the Model S was running version 7.1.
David Zuby, the institute's chief research officer, stresses that a definitive ranking of driver assistance systems is not yet ready. In particular, a formal ranking system will take into account both how much of the driving task each system handles, and also how reliable each system is at handling the tasks it does undertake.
We're not ready to say yet which company has the safest implementation of Level 2 driver assistance."
Even more than relative ratings, Zuby highlights the need for drivers to stay alert. "A production autonomous vehicle that can go anywhere, anytime isn't available at your local car dealer and won't be for quite some time. We aren't there yet."
