I have experienced a sudden acceleration type problem when driving over rough pavement and potholes, etc. The acceleration is for a split second and I suspect it may be related to the lack of traction from the tires. It does not appear to have anything to do with loose floor mats or a sticking pedal. No repairs have been made. Dealer said they never heard of the problem when I went in last week. I was offered to have it brought into service depart. It does not happen on command so I am going to wait for NHTSA investigation.

- Mahwah, NJ, USA

Design flaw on a brand new 2010 Toyota Prius that makes rattling noise near the gear shift lever that could brake the gear lever.

- Princeton, NJ, USA

I was driving my 2010 Toyota Prius using cruise control on a highway. I disengaged cruise control to slow down as a vehicle entered the highway in front of me. Once the second vehicle had accelerated ahead, I re-engaged cruise control at my desired speed. The cruise control engaged, but continued acceleration, as if I was activating the cruise control mechanism's accelerate "paddle", which I was not actually doing. I immediately dis-engaged cruise control, slowed to my desired speed, and re-engaged cruise control. At this point, the cruise control resumed proper operation and I was able to drive at my selected speed.

- Guilford, CT, USA

2010 Toyota Prius. I have experienced on at least 3 occasions, a surge when going over a bump or pothole. I spoke to my law partner about it yesterday. Today he showed me the investigation you have opened into this issue.

- Jacksonville, FL, USA

While turning off four lane road onto frontage road with foot on brake pedal my car suddenly started accelerating. I applied more pressure on the pedal quickly and got a sort of clunking sound and the car returned to normal driving speed?

- Rotonda West, FL, USA

Toyota Prius 2010. Problem reported to dealer 12-18-2010. Brakes become inoperative when passing over uneven surfaces, vehicle also at this time vehicle lurches forward. This occurs frequently. Contrary to your form requirements there is no one "approximate incident date". shifter sometimes is difficult to put into neutral, rather it will instead go from drive to reverse. If there is also a sudden acceleration problem, this could be a big problem when trying to regain control.

- Needham, MA, USA

I have a 2010 Toyota Prius that I bought in December, 2009. Six or seven times, I have noticed that the car lurches forward (like someone is flooring the gas pedal) every time I hit a pot hole. I thought it might be just me, but I saw in the paper today that others have noticed similar problems with their Prius.

- Santa Cruz, CA, USA

Car did not brake properly and slightly surged forward on many occasions when I drove over a manhole cover and speed bumps at lower speeds. In one occasion, I rear ended a car and cracked my license plate frame but since there was no further damage on any of the cars involved, we agreed to drive away.

- St. Paul, MN, USA

On three occasions, my 2010 Prius "leapt forward" when I drove over a man-hole cover. I have read the description of the braking issue on the 2010 Prius and it sounds exactly like my experience. It only lasts for a fraction of a second, but it is quite frightening when it happens.

- Denver, CO, USA

The contact owns a 2010 Toyota Prius. The contact stated that while driving 10 mph and engaging the brake pedal, the vehicle briefly accelerated on its own and the brakes malfunctioned. The failure has occurred 10 times since the vehicle was purchased. The dealer was contacted and they stated that was a safety feature. No repairs were made to the vehicle. The failure mileage was 500 and the current mileage was 4826.

- Los Angeles , CA, USA

2010 Prius which lurched forward each time I hit a certain pothole while braking. I avoided the problem by avoiding the pothole. The pothole was located near a stop sign, so I was always braking when I hit it.

- Ann Arbor, MI, USA

The contact owns a 2010 Toyota Prius. While driving 20 mph he applied the brake pedal; however, the vehicle did not slow down instead it accelerated at various speeds. The dealer was unable to duplicate the failure during a test drive. He stated that the failure occurred six times intermittently contact is concerned that if he continued to drive the vehicle the failure could cause a crash to occur. The failure mileage was 9,000 and the current mileage was 10,500.

- Reston , VA, USA

When driving and braking, if you hit a bump or pot hole, the brakes release and the car doesn't slow down. This has happened a number of time since I bought the car in August 2009.

- South Jordan, UT, USA

Braking while driving over a pothole causes the 2010 Prius to momentarily feel like it's accelerating rather than braking. This has resulted in near-accidents a couple of times. This happens more consistently when turning while braking over uneven pavement. I can repeat this reliably in specific location, and it happens elsewhere too.

- Madison, WI, USA

On at least two occasions, I have had uneven, jerky acceleration from my 2010 Toyota Prius. Acceleration was from a stand still and was at low rates of speed. Both instances have occurred when the vehicle was cold, but the ambient air temperature was probably above 30 degrees.

- Thornton, CO, USA

I own a 2010 Toyota Prius..purchased in August 2009...currently going for 15K miles on the odometer. I want to report issues with sudden acceleration even when I am stepping on the brake. I noticed every time I pass thru uneven road, for example potholes, icy roads, snow. The most common issue I have is as I am going down the road and car hits a pothole or manhole (those with metal covers) the car will suddenly accelerate, although I am stepping on the brake. Sometimes I am afraid I will hit the car in front of me, especially when im in traffic. Even going at 5-15 mph, the car will accelerate when it hits uneven road like pot holes or icy roads. This has happen quite a few times since I purchased the vehicle. Just yesterday, we had about 1-2 inches of snow. I was driving slow and when making a left turn, the car hit some uneven road and snow and accelerated when I was stepping on the brake to make the turn. The car went up the sidewalk and the bumper cracked as it hit the concrete edge that separates the road and the sidewalk. No one was hurt and no property damage was done. The car is working fine, but this sudden acceleration issue is a major concern, especially now that I read and hear in the news that 2010 Toyota Prius are being reported with complaints of sudden acceleration. I thought my issue was an isolated case. Please take this complaint into account. I will be going to the dealership this weekend for the 15K scheduled maintenance and will report the issue to them.

- New Brunswick, NJ, USA

When slowing down over bumpy surfaces, the car temporarily loses braking control (for a second or so). It is terrifying and needs to be looked into. There are hundreds of people online who have reported this exact same problem.

- Saratoga Springs, NY, USA

I own a 2010 Prius and took the car into the local Toyota dealer 2 days ago for the initial 5,000 mile check up to discuss a couple issues I have found with the car. I have experienced on 3 occasions a feeling of brake failure. This has occurred when I am driving over rough road. While the brake is being applied if I hit bumps, the brake pedal drops and I lose the brakes. I have immediately let up on the brake and then reapplied pressure to the brake pedal to get braking back. The dealer tried to achieve the same problem but was unable to replicate it. He said it was just the way the pedal must feel to me. Our daughters both have 2006 Prius' which I have driven and never experienced this problem with their car brakes. The second problem is with cruise control. Again, I have driven a 2006 Prius and used cruise control and not experienced the following in the 06 model that occurs in our 2010 model. The car started to accelerate in cruise mode. We have also found it takes a lot of pressure on the brake pedal to take it out of cruise control. The car jerks when tapping the brake pedal lightly to take off cruise control. The dealer again took it out for a test drive and said this is the way the Prius feels. I know driving the 2006 model it was not the way the Prius feels when you take it out of cruise control.

- Bannockburn, IL, USA

2010 Toyota Prius spontaneous acceleration while braking over bumps, pot holes and slick roadways.

- Farmingdale, NY, USA

2010 Prius seems to lurch forward when driving over potholes and other bumps while braking. This has happened near intersections and when turning into parking lots. The car seems to speed up briefly, enough to scare the driver. I've almost rolled through stop signs and nearly run over a few cars when turning into parking lots.

- Columbiana, OH, USA