Automatic Emergency Braking problems of the 2021 Lexus RX

I was at the gas station, in line waiting for one of the three gas pumps to be available. I put my car in reverse to back up and pull around another car in order to go to the open pump in front. When my car was in reverse motion, I stepped on the brake pedal, but the car did not stop. I stepped on the brake pedal numerous times, but the brake did not function. My car backed into the front of the car in line behind me damaging both vehicles. The automatic emergency braking system did not activate, and there was no rear collision warning sound or message. I switched my car from reverse into park to stop its movement, but it was too late to avoid the collision. I had a passenger in my car who corroborates this description. Fortunately there were no pedestrians behind my car, so the only damage was to the vehicles. My vehicle has not been inspected by anyone since the accident, but will be soon. I have owned this car since April 2021 and previously had a few similar situations when moving in the forward direction. Previously, the brake problem occurred while moving forward at very low speed pulling into parking places. The brake failed to activate, and I had to throw the car into park to stop it, but this was the first time I had experienced this problem traveling in reverse. When this situation occurs, I am pressing on the brake pedal, but the car is not stopping and the brake pedal seems to go to the floor. On March 5, 2025 I took the car to a Lexus dealer and reported the brake failure problems. They inspected, road tested, and checked for codes, but could not identify the problem. I believe that the collision back up system should have prevented this accident, but it did not function. I suspect that there may be some kind of computer issue that prevents the brake from actuating. The car will be going in for repair soon, and I have requested that a complete diagnostic review be performed of this brake problem.

The pcs detected another car in front and my car went into park, but kept rolling and the engine revved to 7500 rpm.

The sole occupant driver drove into a slightly elevated driveway and stopped. The driveway is maybe 5 degree incline. The shift select lever was placed in park and the driver visually confirmed it was in park. Driver sat in the car for 12 seconds before exiting the vehicle with the engine running and ac on. The driver exited and was standing outside of the vehicle with both feet on the ground for 6 seconds reaching back inside at which time the vehicle began to suddenly roll down the driveway causing injury to the driver. This seems to be a failure of the parking system of the vehicle causing serious injury to the driver. The vehicle has not been inspected yet and investigation is ongoing. It is unknown if there were any warning lamps, messages or other symptoms of the problem prior to the failure, but there was no prior service work performed on the near new vehicle. There is a video of the incident.