While traveling on the interstate, the driver of the Ford Escape moved into the left lane from behind an 18-wheeler that had stopped while attempting to enter a turning lane. After moving into the left lane, the driver observed traffic ahead stopping. The vehicle ahead was at or beyond the front of the 18-wheeler. The Escape was still behind the rear of the 18-wheeler when the driver began braking. The driver pressed the brake pedal, but the vehicle did not stop as expected. It may have slowed slightly at first. The driver released the brake pedal and pressed it again. On the second application, the vehicle did not appear to slow further, and the brake pedal felt as though it went straight to the floor. The driver continued holding the brake pedal down until the Escape collided with the vehicle ahead, which was at or beyond the front of the 18-wheeler's cab. The driver had applied the brakes twice before the vehicle's forward-collision/impact warning activated. There were no known brake warning lights or brake-related messages before the incident. The suspected system involved is the braking system; the exact cause is UNKNOWN. The collision resulted in the vehicle being declared a total loss by the insurance company. The vehicle is currently being held at the insurance company's investigation yard and has not yet been released to the salvage department, so it remains available for inspection at this time. During approximately three years of ownership, the vehicle had prev