While braking over a rough surface such as potholes, train tracks or just rough pavement, the brakes feel like they cut out for a brief (well under a second) period. This could be ABS activating or it could be the changeover from regenerative braking to friction braking or something I am not aware of. I would describe the feeling as "floating" or hitting a patch of extremely slippery ice or like my foot has slipped off the brake pedal. I am confident that this event increases stopping distance but I have no idea how much and it may only be inches. I know from reading, this has been reported years ago with the previous generation Prius. Overall, I am extremely pleased with the car but this is something I believe should be investigated. Oh yes, it is fairly easy to reproduce and has happened to me 3-5 times in the 6000 miles I have driven the car. It is not nearly as terrifying now as it was the first time but when it happens it definitely grabs your attention! it has not caused me to get in an accident but I believe the potential is there for an accident to occur.

- Clarkston, MI, USA

I own a 2010 Toyota Prius, and like many have experienced the brakes "cutting out" when slowing down and going over a rough section of road. I drive throughout the houston, Texas area and have had this issue happen many times, usually unexpectedly. There are a few places I drive regularly that create the issue and I anticipate them and adjust my driving accordingly.

- Houston, TX, USA

2010 Toyota Prius with 2500 miles. Since purchased on 8/2009, I had more than ten experiences of unexpected acceleration (sudden unintended acceleration) on reverse that feel like two or three time (stronger) faster than normal reverse. Accompany the higher speed reverse, a heavy, abrupt braking with a slight touch of the brake during this event. The big "jerk" (braking) rock the entire car and banged heads again the headrests.this only happened with electric mode and most time with the car parked a slight incline. This unintended acceleration sometime happen a few time a day or it can go two, three weeks without any problem. The dealer can not find anything wrong with my car. And Toyota have no information about this problem. However, if you go to priuschat forum under gen III 2010 Prius main forum-braking in reverse, there are many people with the same problems. I strongly believe this is very dangerous if a new driver get in my car and not know about it. There is one post in priuschat forum that best explain the problem: Just yesterday, my Prius-III backed up with sudden unintended acceleration, with my foot only on the brake pedal.... I recognized what was happening because it happened once before, just over 2 months ago. Just a few days after I got the car. When I was backing out of an inclined driveway... I suspect that some unusual element of the timing of turning the car on and shifting into reverse, and possibly the internal state of the computer and the hybrid power system combine to produce this "abrupt" reverse acceleration as I am gently easing off my foot pressure on the brake pedal... the abrupt braking effect does occur, but only in response to the much more dangerous "unexpected, unintended" reverse power (acceleration), to stop the car motion. No matter how gently the brake is eased further on to stop, the stop is "abrupt" by garygid orange county, ca. I am trying to work with Toyota on this issue. Thank you.

- San Francisco, CA, USA

2010 Prius "freewheels" if you hit a bump while braking. This occurs every few weeks. Nothing has been done to correct.

- Jenkintown, PA, USA

I was unable to slow down going into an intersection at a reasonable rate of speed. While I was not accelerating, when I applied the brakes the car did not slow down as I would have expected. This same behavior has occurred in the past several months since I've owned the Prius 2010 model. It seems to skip forward or accelerate while braking on a downhill or uneven surface. By the time I was able to stop I the airbags had gone off and I had hurt my neck and back. It is a new vehicle that now has almost $14,000 damage and won't be fixed for a month. If anything, I'm an overly cautious driver and wondering what I could have done to avoid the accident.

- Cave Creek, AZ, USA

My 2010 Prius V has very jerky brakes sometimes when starting out. Causes all people in car to be jerked around. Many other Prius 2010 owners report same problem. Toyota denies knowing about problem in spite of many complaints!

- Harrisburg, PA, USA

I bought a brand new 2010 Toyota Prius and left the dealer on October 23, 2009. I had to stop short at one of the stoplights on the way home and noticed a disturbing lag before the brakes engaged. Hours later I was driving down a major highway when traffic stopped suddenly and the brakes would not engage. I rear-ended the car in front of me and modestly damaged the car I hit and severely damaged my new Prius. Fortunately noone was hurt. My six year old son was in the back seat.

- Dallas, TX, USA

Please investigate the 2010 Prius and its' braking system. While braking on a wet pavement, going down hill or braking when the car goes over an uneven or bumpy service, the car accelerates or lurches forward. Fortunately, I was a safe distance from other cars or could have hit something with this surge effect. The car only has 400 miles and this has occurred at least 4 times, the most recent today on a hill with wet pavement as the car was heading down hill. The brake was gently depressed and the car surged forward.

- Washington, DC, USA

The contact owns a 2010 Toyota Prius. While driving over large and small speed bumps the vehicle accelerated without warning. As a consequence his risk for serious injury and crash were increased. He is in the process of having the vehicle inspected to determine the cause of the failure. The failure and current mileages were 1,000. Updated 09/14/09 the consumer stated on 6 separate occasions, with 2 different drivers, sudden, brief and unexplained engine acceleration was experienced when a bump was hit in the road while applying the brakes. The driver could hear the engine rev up and there was a surge of power from the engine despite his foot not being on the accelerator, but being on the brake. In each of the 6 incidents the consumer and second driver were able to stop safely, bit were put at risk of an accident and/or injury due to the erroneous acceleration. Updated 09.15.09. Updated 10/13/09. The consumer stated the cruise control was not engaged and it didn't feel like the anti-lock brakes engaged either. Updated 10/13/09 the consumer also experienced braking problems as well. The consumer stated the problem has greatly diminished. Updated 02/05/10.

- Lansdale, PA, USA