Car And Driver: We Crash Four Cars Repeatedly to Test the Latest Automatic Braking Safety Systems [1]
"To understand the strengths and weaknesses of these systems and how they differ, we piloted a Cadillac CT6, a Subaru Impreza, a Tesla Model S, and a Toyota Camry through four tests at FT Techno of America's Fowlerville, Michigan, proving ground. The balloon car is built like a bounce house but with the radar reflectivity of a real car, along with a five-figure price and a Volkswagen wrapper. For the tests with a moving target, a heavy-duty pickup tows the balloon car on 42-foot rails, which allow it to slide forward after impact.
The edge cases cover the gamut from common to complex. Volvo's owner's manuals outline a target-switching problem for adaptive cruise control (ACC), the convenience feature that relies on the same sensors as AEB. In these scenarios, a vehicle just ahead of the Volvo takes an exit or makes a lane change to reveal a stationary vehicle in the Volvo's path. If traveling above 20 mph, the Volvo will not decelerate, according to its maker. We replicated that scenario for AEB testing, with a lead vehicle making a late lane change as it closed in on the parked balloon car. No car in our test could avoid a collision beyond 30 mph, and as we neared that upper limit, the Tesla and the Subaru provided no warning or braking. (Emphasis mine)
Our tests also exposed the infallibility myth that surrounds computers and automated vehicles. Driving the same car toward the same target at the same speed multiple times often produces different results. Sometimes the car executes a perfectly timed last-ditch panic stop. Other times it brakes late, or less forcefully, or even periodically fails to do anything at all. In our stationary-vehicle test, the Impreza's first run at 50 mph resulted in the hardest hit of the day, punting the inflatable target at 30 mph. It was only on the second attempt that the Subaru's EyeSight system impressively trimmed the speed to just 12 mph before the collision. All the results in the charts in this feature show a car's best performance."
Note that these tests were executed against an object intended to replicate the radar profile of a light vehicle. I expect worse results against a semi's trailer. Tesla is not alone in facing this challenge.
To be clear, these systems are a net win: without automatic emergency braking, fatality rates would be much higher. People will still die, but less people than before.
[1] https://www.caranddriver.com/features/a24511826/safety-featu...