NHTSA Complaint #11449744 — 2021 GMC YUKON XL

On Wednesday, January 12, 2022, while driving from Columbia, SC to Cincinnati, we were heading northwest through the mountains of North Carolina, on I-40, just east of the TN border. Traffic was fairly steady and heavy, so we were traveling at approximately 45 MPH, in the right lane, winding through the mountains. Our friend, ** ***** was driving, my wife, ********* *****, was sitting in the right front passenger seat, working on her laptop, and I was sitting immediately behind her, also working on my laptop. With a semi-trailer truck slowing ahead of us, *** signaled to make a lane change into the left lane (this is only a two lane highway). As we were transitioning to the left lane, the vehicle suddenly – without any warning or driver inputs – slammed on its brakes, bringing the truck to a sudden and violent stop. Given the violent halting of the truck, we all assumed we had been rear-ended by a truck. The braking was so serious, luggage from the rear of the vehicle shot forward like a missile, striking my wife in the back of the head. She suffered what we believe to be a concussion, and she did seek medical attention in the days following the incident. Sitting behind her, the sudden stopping action caused me to twist my left knee, resulting in what might be a cartilage tear. I also saw my physician in the days following, and he acknowledged the swelling of the left knee. He advised me to monitor the knee carefully, and if the pain persists, to get an MRI. The pain has not gone away, and I plan to get an MRI in the next week or so. Our friend suffered a severely strained back in the incident, and has been treating his back with both ice and heat therapy. This was the THIRD time this happened, each nearly resulting in a tragic accident. The dealer said "it's just a software glitch." The "Brake Assist" program is clearly defective and unsafe.