NHTSA Complaint #11505915 — 2021 TESLA MODEL Y

SYSTEM MALFUNCTION: Emergency braking ("phantom braking") while set to automated driving/adaptive cruise control. OUR SAFETY PUT AT RISK: On a 2,000 mi. road trip from Denver CO to Tucson, AZ and back, the vehicle slammed on the brakes at 75-80 mph speeds over two dozen times. All incidents occurred either driving south on I-25 or west on I-10 going to Tucson, or on I-10 east and I-25 north on our return. By far the most dangerous event occurred when we were driving east on I-10 in SE Arizona on our return to Denver on 29 January. Driving in the right lane at 75 mph on a perfectly clear day with excellent road conditions, the vehicle suddenly slammed on its brakes. Following closely behind us was a semi-tractor-trailer, that also slammed on its brakes, blasted its horn, and very nearly rear-ended us. The truck driver then followed us at very close range for the next ten miles, If we slowed down, the truck slowed down. If we speeded up, the truck speeded up. We disengaged cruise control so we wouldn't involuntarily brake hard once more. Finally, the truck drive honked once more and dropped back as we sped up. In our view, this was an evident case of road rage on the trucker's part that might have ended tragically. REPRODUCTION OF PROBLEM: We have a 2/27/23 appointment with a Tesla service center here in Colorado to check out the automated driving/cruise control/camera and sensing system. However, this problem only arose under quite specific topographical, and road surface/light conditions on I-25 and I-10 in rural areas, so I'm doubtful Tesla service techs would be able to replicate the conditions. WARNINGS: There were no warnings emitted by the vehicle either audibly or visually (on the display screen) prior to any of these incidents.