Driving on a 4-lane highway when a box truck directly ahead stopped quickly due to a stopped car ahead of it. The forward collision warning flashed and beeped, but when forcefully applying the brakes, the brake pedal only pulsed (like anti-lock brakes) but didn't slow the car even enough for the driver or passenger to feel any inertia moving forward in their seats or with their heads. The automatic emergency braking also didn't work, leading to a rear-end collision forceful enough to push the box truck into the car in front of it, apparently injuring the driver of the front car who was transferred by emergency personnel to a nearby hospital to seek medical evaluation/assistance. After impact, a message appeared on the dash stating "Pre-collision assist not available", but the forward collision warning worked, there was no prior warning of issues for the pre-collision assist, and the warning message was after impact, which significantly damaged the front portions of the vehicle (estimated damages exceed $24,000). There was a recall for the same model and year of this vehicle for pre-collision assist features/software not working properly, but it either didn't apply to this specific vehicle or was already addressed by the dealer, and the details aren't quite the same as what was experienced in this collision.