That skepticism is warranted, according to Greg Brannon, director of automotive engineering at AAA. “You can’t sell consumers on the future if they don’t trust the present,” he said in a statement.
About half of new vehicle models offer some combination of lane centering assist (LCA) and adaptive cruise control (ACC) that can be used at the same time to automatically steer, brake, and accelerate in certain situations, according to CR’s research. When CR surveyed our own members, over half of them told us that these active driving assistance systems make driving less stressful. But all the features still require an engaged human driver behind the wheel.
“The driver must stay vigilant and in control of the vehicle at all times,” says Kelly Funkhouser, manager for vehicle technology at CR. In addition, most new vehicles have some form of automatic emergency braking (AEB), and many of those systems can also detect pedestrians and cyclists.
At the same time, many automakers are making promises about a self-driving future, and Tesla has repeatedly said that its current active driving assistance systems will gain self-driving capabilities. But AAA’s tests of today’s technology show that even the most advanced vehicles cannot avoid some collisions, even at low speeds.
• None of the three active driving assistance systems tested by AAA could avoid a collision with an oncoming car that crossed the center line of a straight road. The stakes were a lot lower on AAA’s test track than on most real-world roadways: AAA testers used a foam “target car” and gave the vehicles 1,000 feet of separation. Speeds were just 15 mph for the target car and 25 mph for the test vehicle. Only the Tesla detected the oncoming vehicle, although it was unable to brake enough to avoid a collision.
• When a cyclist crossed its path 290 feet ahead, the Subaru EyeSight’s AEB system was unable to detect it or stop in time to avoid a crash—even at just 25 mph. The Hyundai and Tesla systems were able to stop in time.
• All three tested systems avoided a crash with a slow vehicle in the same lane ahead, a simulation of what it would be like to encounter traffic congestion on a highway. In addition, all three systems avoided crashes with a cyclist traveling in the same lane in the same direction.
Though there were differences among the systems, AAA project technical leader Matthew Lum told CR that ranking or differentiating their performance wasn’t the intent of the project. “The primary objective is to illustrate [active driving assistance] system performance as a whole in the context of real-world situations that drivers may reasonably encounter,” he said.
In a statement, AAA’s Brannon said that drivers often say they expect such systems to perform flawlessly. “But unfortunately, our testing demonstrates spotty performance is the norm rather than the exception.”
Earlier this year, AAA found that many AEB systems with pedestrian detection don’t work as well at night or when vehicles are taking a turn.
Despite their limitations, systems such as AEB have been proved to reduce crashes. CR recommends that car buyers seek AEB on their next vehicle.