I applied my brake pedal to slow for traffic just before entering a roundabout. I came nearly to a full stop, but then with my foot still on the brake pedal, the car surged forward as if I had floored the gas pedal. I kept pressing very hard on the brake pedal, but the car kept speeding forward. I was able to steer in between 2 oncoming cars without hitting them. My left front tire then hit the curb and the car bounced off a metal traffic sign post. I then went down a steep dirt embankment and crashed into a swale with some large rocks. My car finally came to a stop, rim deep in soft dirt just off the shoulder of the road. I did not notice any warning lights come on. I don't know what system malfunctioned, but it had something to do with fuel delivery and possibly the cruise control and automatic braking functions. I was very lucky I was not injured. This malfunction could have caused a serious and possibly a fatal crash. This malfunction put me and nearby motorists at risk of being hit by an out of control vehicle. I checked the floor mat and it was not displaced. There were no loose objects that could have affected the gas or brake pedals. The police officer accused me of stepping on the gas instead of the brake, but that was definitely not the case, regardless of what he may write in his report. The car is currently at a local collision repair shop. They will be checking with the code reader to see if any codes come up involving the fuel and braking sys