Coming down a steep, narrow, long driveway leading from a private home on a hill, and moving forward in low gear, I allege that the brakes failed. After 3-5 attempts at braking, we came off the cement driveway as we accelerated and slid off the side of the hill, turning over onto the driver's side of the car and coming to rest near a dropoff, held by the branches of an oak tree. Fire engines came, and the Jaws of Life were applied, basically demolishing the car (which did hold together as we slid along). The seat belts also did their job. The car was removed from the towing yard in Grover Beach, CA, to Fresno, CA, whereupon the car's computer was inspected by an engineer hired by Lexus. He reported no failures. Besides me, the driver, there were two other occupants. My sister has sustained whiplash, and her boyfriend is having some pain in his hip. I seem to be fine. The other occupants were held in place by the seat belts. I was held by my belt and was also resting against the side air bag on the driver's door. The passenger's front side air bag also deployed. There is no confirmation of a problem by the dealer or an independent service center, unless the engineer counts as independent. Other than the engineer, I don't know of any inspection of the vehicle. The Highway Patrol was on the scene but did not write a report as we were on private property. No warning lamps came on that I observed.