Was doing 55-60 mph in left lane of highway. Suddenly and without warning the car is decelerating, cannot accelerate any more, all warning lights suddenly flashing on dashboard. I was able to get over to the far right emergency lane, turn car off and put on hazards and started calling Subaru roadside assistance. While doing so I suddenly saw smoke coming out from under the hood. I got out of the car and continued my talk when the smoke suddenly turned to flames from under the hood and I called 911. Within 3 minutes of dialing for assistance, my car was completely engulfed in flames and it was burned to a crisp by the time the fire trucks put it out. My insurance company retrieved the car from wherever it was towed and has assigned it to someone to investigate.