Automatic Emergency Braking problems of the 2018 Toyota Avalon

The pre-collision braking system does not appear to work. Several times when cars in front of us have slammed on their brakes, the pre-collision braking system does not respond. We own a 2016 prius with the same feature and it always responds � flashing a warning and applying the brakes. We complained to the dealership multiple times, and they said the system in our car performs a check every time we turn on the car and since it does not indicate a fault, to their knowledge the system is working fine. They said there are no other tests for them to perform. I've adjusted the system to the most sensitive mode (active when vehicle in front of us is further away), but this has had no effect. Also, the adaptive cruise control which uses the same radar system as the pre-collision braking works fine. There definitely is something wrong with the pre-collision braking, and I am concerned that this safety feature will not save us from a collision. The only way someone would be aware that the system isn't working is to experience a near collision. I believe the pre-collision braking system could be tested without damaging our car by placing a large stationary inflatable object in front of our moving car. I would be glad to provide our car for you to perform such a test or another test that you may have developed. This may be a problem with many other Toyota Avalons and other cars.