Illinois I-94 Westbound near Torrence Ave. Exit 5:35/5:36AM 2/5/2025 cruise set at 70mph, passing 18 wheeler on my right and a car was passing me on my left. No car in front of or behind me in my lane of travel. Vehicle braked hard all by itself. I had to cancel the cruise control to stop the braking. This could have been bad had there actually been another vehicle directly behind me when this happened. It has happened before but I did not record the details. I will be making a written record of this failure and reporting it every time it happens.