I was pulling my 2011 Toyota Siena into a parking space. My foot was on the brake and the car was going about 5 mph. The car made a slight sound, along with a perceptible yet small physical shift, and (while my foot was on the brake) independently accelerated with tremendous force. It was like it was ignited. The car hit a concrete pole and was totaled. The acceleration over-rode the brake. No one was hurt. The concrete pole averted what could have been a catastrophic accident, had we hit pedestrians, or had we rear ended a car or truck on the freeway. The brakes failed as the car jumped into independent acceleration. My safety and the safety of my passenger were both at risk. As I said, in a different situation, we might have hit pedestrians, or gone through the wall of the grocery store and hit customers. The concrete pole saved us and others. The mechanic at the service center where the car was towed said it was impossible to discern if there had been a failure in the system of the car - though clearly both my passenger and myself experienced that failure in the car's ability to override an independent, forceful acceleration not caused by the driver. There was no warning of any kind. On the Edmunds site, there are many, many testimonials by other drivers of the Toyota Siena of similar, frightening experiences of independent acceleration. It is terribly dangerous and should be investigated. If there is not a recall on this vehicle, there should be. This is a potentially cat