The following event happened twice with this vehicle. Tin both instances, the car was running and in park with no one in the vehicle. It then down the driveway with no one in it. In the second occurrence, it appears to have gone into reverse on its own and rolled into a retaining wall causing damage to the rear passenger side bumper and back panel.

- Sioux Falls, SD, USA

Problem with 2010 Prius performing uncontrolled hard braking while driving on interstate at approx 73~75 mph. This happen on two separate occasions, with the first being Feb 10, 2013. The second incident occurred late afternoon on sat. Feb 16, 2013. Both occurrences were in light traffic, whereby preventing potential severe vehicular rear end collisions that could have resulted in serious bodily injures and grave vehicular damages. Vehicle was checked by a Toyota dealer and passes all troubleshooting tests, Feb 18, 2013. Requested additional tests be done on Feb 19, 2013. Toyota dealer could not recreate the problem. No further actions were taken by the dealer.

- Frankfort, KY, USA

This is a recurring problem. Anytime I am slowing down for a red light and there is a pothole or other rough surface condition, the car lurches forward and jumps, so to speak. Given the condition of the roads in Chicago, this is a pretty regular problem. I usually have to press the brake much harder than normal while this is occurring because of crosswalks and lights. I think this is a serious safety issue; however, when asking the dealer to look into this, they indicated that it was the anti-lock braking system kicking in, and that it was a perfectly common thing to experience.

- Lansing, IL, USA

All brakes failed while I was going 69mph on I-75 South just North of the union centre boulevard exit, approaching I-275 at the butler/hamilton county line on sat. Dec. 22.. all warning lights came on and the warning "beeps". I was in heavy traffic but was in the right lane and was able to exit on the union centre exit ramp and roll to a stop. This happened the day after I had the car at performance Toyota in fairfield, oh for the 35,000 mile check/oil change (on Dec. 21).the car had to be towed to performance Toyota on Dec 22; they determined the master cylinder failed (lost its vacuum) causing total brake failure.

- Liberty Township, OH, USA

Incident #1 brake: On January 17, 2013 as I was entering the intersection about 20mph, I applied my brakes, but they went straight to the floor and warning light started blinking. I pressed brakes very hard and car almost stop, then, its brakes gave up. There is sudden slight "unintended acceleration" and I almost hit car front of me. But, I am able to manage to drove the car into the center island. Brake was totally out, and the car started drove by itself. I panicked and pressed power button to shut off the engine. Car drove about 15 feet and stopped. After this incident, I tow my car to the dealer, they told me that lost brake is due to short circuit made domino effect to multiple computers malfunction. They will replace whole computer system, but service man would not guarantee it will never happen again. Incident #2 power failed and shut down while driving at highway. On December, 2012 and January 2013. I was driving at highway and trying to merge into the center line, car stalled and prompted "key does not detect" message on the screen. I almost hit from behind by another car. While the car still has a speed about 40mph, I managed to restart the car by depressed brake and press power bottom. It is true this car lose brake and does slight "accelerate".

- Orange, CA, USA

When driving on an uneven or wet surface the brakes seem to lag for a few seconds and the car hops forward.

- Ellicott City , MD, USA

My Prius iv, purchased new in 2010, intermittently had a lunging forward problem when going over speed bumps, pot holes etc. I would have to stop it by braking quickly, so I didn't collide with a car ahead. I informed Toyota of this problem within the first year. They tested it and said they could find nothing. I mentioned this to them on various occasions when I took the car for its periodic maintenance of 5000 mile intervals. On December 26, 2012 I was stopped waiting to go left when I was rear-ended. I went to pull over to the side of the road to assess the damage. When I accelerated to get to the side of the road, the car took off crazily, at a high rate of speed for about 6-7 seconds, zigzagging uncontrollably on the 2 lane road. If there were cars coming toward me, I would have been in a head on crash. I immediately called Toyota service of scranton, pa and asked them to see and assess the car's problem. They made an appointment and concluded.said there is no problem internally, and suggested removing the after market floormat. I then proceeded to show them the same problems many customers are having with the Prius, including an article by steve wozniak, the co-founder of apple company, who had acceleration problems with his 2010 Prius. I called the main Toyota headquarters later, explaining the problem and they too said there is no malfunction, only mentioning the floor mats again.. this is not the case as the car has had acceleration problems from the beginning and to further clarify, I was able to finally stop the car... the mat was no where near the accelerator. I am afraid to drive this for others' safety, my passengers and my own safety. I take care of my cars faithfully. You can view my records. I am also fearful if I trade this car, someone else might get injured or killed. Can you please check and advise.

- Swoyersville, PA, USA

If you go over a bump while braking - the brakes fail, and you have to take your foot off the brake and re-apply in order to stop. This has occurred numerous times - and is a serious flaw on this automobile. This car is a fleet vehicle for my company and I have asked peers if this occurs on their cars - and they have confirmed the same experience with their brakes. With all the Toyota recalls - I am unclear why this has not been addressed...?

- Chicago, IL, USA

I was in the right lane traveling West bound on Tennessee street in tallahassee, fl, and as I was going through the light at the corner of Tennessee and monroe street, the traffic stopped just past the intersection. As I was entering the intersection, I applied my brakes but they went straight to the floor and a warning light started blinking. I had one of two choices; hit the car in front of me or hit the curb for the sidewalk close to where a man was standing with his bicycle. Luckily I had just enough room to go between the back-end of the car in front of me and the man on the sidewalk. Fortunately no one was injured in my accident, I just scared the man very badly, but the repairs to my car are probably going to be more than $4,000.

- Tallahassee, FL, USA

Ok, this type of incident (loss of braking at low speeds) has happened repeatedly in this vehicle, despite a recall in 2010 and "software fix". the date listed is approximate. I felt compelled to provide this information after having this happen twice in the past week, in the hopes that some permanent fix can be made available, and to warn prospective buyers to be cautious. In all incidents, when traveling over bumps in a road with the brakes engaged, there is a sudden slight "acceleration", but in actuality, probably just the momentary loss of braking. This happens when going over: (1) manhole covers (2) potholes (3) slight dips in the road (from subsiding road patching areas). Does not appear to be worse in wet conditions, and has only happened to me at low speeds (~5 -- ~ 20 mph). Note that original carpeted mats were replaced with ones that fit a bit better, and do not cause any issues with the acceleration pedal. Once the bump is passed over, normal braking occurs. When I feel this vehicle momentarily lose braking, I quickly let off the brake for a split second, and resume braking. I have gotten used to this defect, but I sure would like someone to investigate and provide a quality recall fix. This braking issue has happened in North Carolina (where the vehicle was purchased) and in Massachusetts. Thank you.

- Newton Highlands, Ma, MA, USA

When I encounter a bump while applying the brakes in my 2010 Toyota Prius, the brakes fully disengage momentarily. This causes the car to jolt forward unexpectedly. My foot is not coming off the brake at all when this happens, so I know I am not the cause of it. I received a recall notice by mail in February 2010 to address just this issue. I took the car to the nearest Toyota dealership to have the recall work completed. It was intended to fix the malfunction in the anti-lock brake system that caused the brakes to disengage when the car hits a bump. The recall work was completed, but the problem was not resolved. The brakes still do the exact same thing and fully disengage when I hit a bump while braking. This is unquestionably dangerous and a serious safety hazard.

- Austin, TX, USA

On Tuesday October 02, 2012 at approximately 0510 the vehicle brakes went out and the brake, ABS, and stabilization lights came on along with alarm. Vehicle was towed to Toyota dealership for repair - told it was the master cylinder. Vehicle picked up on morning of October 4, 2012 from dealership drove approximately 20 miles and the exact same thing occurred. Brakes, ABS, stabilization alarms came on. Toyota dealership was called and said that the vehicle should be fine - system had cleared with part replacement - "maybe it was a bad part or there could be air in the lines." Vehicle is presently at the dealership awaiting inspection. Fortunately, no accidents or injuries occurred on these dates. However because of the loss of brakes and near accidents this vehicle is now a threat to my safety. So far I have been lucky - I do not want to take a chance with the third being the time that I am in a serious accident.

- Tucson, AZ, USA

Traveling on parkway when we were approaching a vehicle going South down at approximately 55 we were traveling 72 with cruise control engaged, I tapped the brakes to try and slow and nothing happened I then held the brake pedal down for more than 15 seconds with no success, tried to disengage the cruise by pulling back on the handle on the steering wheel and still it would not disengage, we struck the truck at 72 mph only because we had no where else to go and the vehicle would not disengage cruise. The cruise control light was still illuminated after the vehicle came to rest after impact and the vehicle brakes still did not appear to function, this vehicle was a Toyota lease and was told multiple times by Toyota that the issues was recalled by Toyota and that this vehicle had the recall performed.

- Benton , KY, USA

The contact owns a 2010 Toyota Prius. The contact stated that while driving 15 mph, the vehicle started to lose power lunged forward. The contact attempted to apply the brakes however, the brakes were inoperable and caused the contact to crash into another vehicle. The passenger of the second vehicle claimed an injury and was transported to the emergency room. The police were notified and a report was filed. The vehicle was inoperable and was towed to the dealer who had not yet diagnosed the failure. The manufacturer was notified of the failure who advised that the vehicle diagnosis was going to take four to six weeks and offered no additional assistance. The failure and current mileage was 28,000.

- Lynchburg , VA, USA

Turned on car and noticed alot of the dashboard lights stayed on. As I pressed the brake pedal it felt weird and once I put the car on the drive gear I totally lost brake control, the car kept moving and I was not able to stop. I had to shift to "park" and risk the transmission but better than risking my life... I called a towing truck. The car is at the Toyota dealer and I don't think they have a clue of what's wrong with it.... we'll keep you posted.

- Virginia Beach, VA, USA

The contact owns a 2010 Toyota Prius. The contact was traveling 25 mph and drover over a road bump. The contact applied the brakes however, the vehicle would not respond. The vehicle was taken to the dealer but was not repaired. The manufacturer was not contacted. The failure mileage was 25,000. The current mileage was 75,000.

- Atlanta, GA, USA

The contact owns a 2010 Toyota Prius. The contact stated that whenever braking to drive over any uneven road surface, the braking distance was increased. The contact stated that the vehicle also seemed to push forward as if another vehicle had abruptly crashed into the rear of the contact's vehicle. The vehicle was not inspected. The failure mileage was 36,000 and the current mileage was 38,216. The consumer stated the vehicle was inspected by Toyota. Toyota found no recalls or failures with the vehicle. The consumer stated to the service employee the vehicle lunged, all loose items flew back in the seats and the consumer was thrusted against the seat. The service employee replied that the consumer was mistaken. Updated 09/20/2012

- Knoxville, TN, USA

The unintended acceleration accident happened on 7/18/2012, ~6:20 pm at company's parking lot. I backed my 2010 Prius slowly. Then I saw a car coming on my way. But before I took any action, this Prius suddenly started accelerating, it went wildly, and turned more than 360 degree backward in the parking lot in just a few seconds. Since the car parked between a building and a slop, from the front mirror, first, I saw the building wall and glasses, then I saw the slope, then I saw a car parked close to my car: No! don't hit that car! that is the last thing I remember. Because of the fast turning of the car and because I was so terribly scared, I lost conscious after that until the Prius hit the truck and bounced back and stopped by itself. After a few seconds, I woke up and realized: I am still alive. I got off the car and saw Prius passed the two curbs and hit the truck. The two tires on the driver side got flat because they passed the curb very fast. I was so scared that I couldn't recall of anything for a few days until weekend. Why did the car lose control" one may argue that I stepped on the accelerator. This could happen to new drivers, but not to me because I have been driving for so many years and always a good driver. Many times I saw a car on my way when I was backing, I always stopped right away. And I was healthy in a normal day in normal mode, alert as usual. Why would I step on accelerator when backing? even if I mis-stepped on the accelerator, I can always switch to brake right away. But I could"T do anything about the car on the day. It was out of control completely. After I lost conscious, my hands were off the steering wheel and my foot didn't step on anything, the car didn't slow down but still moved fast and passed two curbs easily. Such a manipulation can only be done when the car is in acceleration, and by itself. Please investigate it asap!

- San Diego, CA, USA

2010 Prius brake failure. I was able to slow down the car by repeated pumping on the brakes. Fortunately, managed to crawl to a nearby Toyota dealer by using the pumping technique and have my foot on the emergency foot brake just in case. Toyota said I need to replace the master cylinder with actuator. Total cost parts/labor $4100. I am upset because my family or others could have been seriously hurt if I panicked and not pumped on the brake to slow the vehicle down. This is a serious hazard which should be known as I have seen other similar complains lodge online.

- Sunnyvale, CA, USA

I applied my brakes approaching a traffic light and hit a small pot hole and the entire vehicle jerked forward even though the brakes were applied and never taken off the pedal. I had to then press down harder on the brake pedal to come to a complete stop. I have observed this type of behavior when the road changes surfaces and is lower than the previous surface and dips in the road. This is all observed while only braking at low speeds less than 40 mph. Every time this behavior is observed there is a loud bang, I am not completely sure if this is from switching surfaces or hit pot holes or dips in the road.

- Houston, TX, USA