The contact owns a 2018 Chevrolet Malibu. The contact stated that while her son was driving at an undisclosed speed with the brake pedal depressed all the way to the floorboard, the vehicle failed to reduce speed. As a result, he collided with the vehicle in the right lane on the rear driver's side. No air bags were deployed. No warning lights were illuminated. A police report was filed, but no injuries were reported. The vehicle was towed to an independent mechanic, who diagnosed a failure with the engine vacuum pump, resulting in a lack of vacuum for the brake booster. The vehicle was not repaired. After investigating the failure, the contact related it to NHTSA Campaign Number 18V576000 (Service Brakes, Hydraulic), but the VIN was not included. The manufacturer was not notified of the failure. The failure mileage was 75,000.