I purchased this car new. During the braking on level or down hill grades, if the road is rough, has pot holes or is like a wash board, caused by transports using the roads frequently, when I have the lever in the "B" mode, the car will take off and go faster, like I have my foot on the gas pedal, but it actually is lightly on the brake. This also has happened in winter months in Michigan and I actually slip off the road a bit but was able to back up and continue. There was a light coating of snow on the road and when it started to take off, the light on the dash came on showing loss of traction. The dealer did nothing as they could not make the problem happen. I was not allowed to take the service advisor for a "test" drive. I contacted our government agency for vehicle safety and got no where with them. I now am lookig at trading in the car and have restarted trying to get someone to listen with our Transport Canada agency. Time will tell. There is a video on the internet that shows a owner with a TV reporter as a passenger, with the same problem. Toyota will not deal with any issue unless people start to die and even then they will drag their feet. "Not a very good feeling", unlike their old ad's used to say, "Oh what a feeling". Their new ad's say, let's go places. In the winter time, I can go bob sledding with my Prius! LOL, but still a sad situation!