2010 Chevrolet Impala cruise control problems

Tl* the contact owns a 2010 chevrolet impala. The contact stated that while driving 40 MPH, the vehicle suddenly accelerated, the steering wheel and brakes were unresponsive. The contact mentioned that the driver lost control of the vehicle causing it to roll over into a river. The air bags failed to deploy. The vehicle was destroyed. A police report was filed. The driver sustained lacerations and bruising. The manufacturer was made aware of the failure. The failure and current mileage was 40,445. Updated 10/7/14

I don't remember the exact date, but approximately 2 yrs ago, I began seeing the sequence of messages, "service traction control, service stabilitrak, engine power reduced," and the engine light comes on along with the traction control system light. The car speed was obviously reduced and I couldn't really accelerate. I took the car back to carmax and they said they couldn't find anything and did not know what I was talking about.