Most major automakers offer electronic driver aids these days, some of which like Tesla’s Autopilot can control the steering of a car. However, the performance levels of driver aids vary across brands and road conditions, in some cases dramatically.
Currently, there’s no independent body that compares the performance of driver aids of different vehicles, with many safety agencies around the world only checking whether a feature is included or not.
The Insurance Institute for Highway Safety is looking to change this by introducing a publicly available ratings program for driver aids. It’s already started testing the effectiveness of driver aids and has come up with some initial results.
For example, evaluations of adaptive cruise control and active lane-keep assist show variable performance in typical driving situations, such as approaching stopped vehicles and negotiating hills and curves. IIHS said its findings show that today’s systems aren’t at the level of a human driver.
Interestingly, the researchers found that driver aids don’t always handle situations in a similar way to what a human would. According to IIHS, when the systems didn’t perform as expected, the outcomes ranged from annoying, such as too-cautious braking, to dangerous, for example, veering toward the shoulder if sensors couldn’t detect lane lines. It’s an important reminder that even with driver aids switched on, one needs to pay full attention.
IIHS conducted its tests on a track as well as on public roads, and the vehicles tested included the BMW 5-Series, Mercedes-Benz E-Class, Tesla Model 3, Tesla Model S and the Volvo S90. One test involved driving at 31 mph toward a stationary vehicle target with adaptive cruise control switched off and automatic emergency braking turned on. In this case, the two Tesla sedans hit the stationary target. With adaptive cruise control switched on, all cars stopped before the target though the S90 braked especially hard.
How active lane-keeping systems performed in IIHS road tests on 3 curves and 3 hills
Another test was for the performance of the active lane-keep assist on the cars, with the results shown in the table above. Here engineers focused on two situations that challenge active lane-keeping systems: curves and hills.
Only the Model 3 stayed within the lane on all 18 trials. The Model S was similar but overcorrected on one curve, causing it to cross the line on the inside of the curve in one trial. None of the other systems tested provided enough steering input on their own to consistently stay in their lane, often requiring the driver to provide additional steering to successfully navigate the curve.
IIHS stressed that it’s too early to say what automaker has the safest system as the testing methods still need to be refined, but with more advanced systems being introduced each year on the road to fully self-driving capability, it’s good to see a rating system being developed alongside.