The contact owns a 2010 Toyota Prius. While driving approximately 50 to 55 mph on normal road conditions pressure was applied to the brake pedal, followed by no power response for a second. The failure occurred intermittently. In addition, when after a complete stop the vehicle began shaking excessively. The authorized dealer and manufacturer have been notified of the malfunctions. The failure mileage was 400.

- Wellington , FL, USA

When slowing down, if the car hits a pothole or bump in the road, it seems to accelerate. As soon as I put pressure on the brake, it stops. It almost feels like the car jumps ahead for a brief moment.

- Wynnewood, PA, USA

Toyota Prius 2010 model: Brake lag. I gather NHTSA is considering a recall. This is to further your data. I took my 2010 Prius in to 355 Toyota, rockville, in November to complain about the brakes disengaging when being applied over rough terrain, leading to a 4 - 6 foot jump forward then re-engagement of the brakes. I lodged this concern as part of getting an oil change service, and I have this complaint in writing on the docket. They told me the problem was just normal antilock braking. The problem has occurred multiple times since, causing about a 4 - 6 foot jump before the brake reengages. With all the ice we have had recently, I can now assure myself that this issue is not about the antilock brakes, which have a totally different feel, as they should. The brake disengagement almost caused an accident on Monday this week on E street as the car hit an ice patch and the brake disengaged momentarily. I think the Prius is a great car, but, this problem is dangerous and needs to be fixed. When I called 355 Toyota yesterday when it became evident that I wasn't the only person reporting this, they were very nice but I am not sure that Toyota has provided them with a solution.

- Potomac, MD, USA

2010 Toyota Prius purchased in October 2009. When braking, car hits a bump in the road or on a rough road, brakes appear to fail for approximately 2-3 seconds.

- Suffolk, VA, USA

Momentary loss of braking when ABS activates causes car to travel an unexpected 12 feet. Has happened 4 times since Dec 2009. Happens when slowing down for stop sign, or making left or right turn in traffic, when there is a slippery patch causing ABS to trigger.

- Kennebunk, ME, USA

I purchased a 2010 Toyota Prius in June, 2009. I noticed that the vehicle seemed to lurch forward when braking - specifically when the road may have even the slightest bump or unevenness. When this occurs, I am not certain that the car will stop. This does not occur during breaking on smooth surfaces. I reported the problem to the Toyota dealer in Nov. And received this response: Wednesday, November 04, 2009 1:05 pm: I'm responding to your question about the Prius braking condition. One thing to know about the Prius braking system is that when the brakes are applied there is a signal to the generator to engage. This does 2 things, helps regenerate the hybrid battery and assists in braking the vehicle, and the normal brakes also apply to assist in braking. I did have another Prius owner ask about this also, I had him come out and drove with him and could not duplicate the stated condition. I think he was pushing to fast and hard on the brake pedal causing the lurch. When I drove his vehicle I did tell him I was trying to be very conscious of how much pressure I was applying to the pedal. I did notice the brakes are very responsive to pedal pressure. Before responding to your E-mail I did check online with Toyota technical group to see if they had any pertaining service bulletins pertaining to your question, there were no applicable bulletins. I hope this helps answer your question. Thanks for choosing seeger Toyota, tim evers, service manager the problem has continued and I've noticed it occurs when braking on snow packed roads -- I nearly rear-ended the vehicle in front of me when my car seemed to lurch forward - I could not stop - I had to swerve into another lane to avoid collision. I reported this problem to another Toyota dealer (weiss Toyota in St. Louis, mo.) they did not have any response. When I contacted the service manager again on 2/4/10, I was told that they had not heard anything about a problem with the Prius from Toyota.

- St. Louis, MO, USA

We have an ongoing problem with our 2010 Prius, purchased in 9/09. When going over a depression in the road, or a bump, when brakes are pressed, we feel like the car is bucking/accelerating. Clearly, it's really that the brakes aren't working momentarily but it's frightening. If we had to stop, we couldn't. this happens each and every time in those circumstances.

- Maplewood, NJ, USA

The contact owns a 2010 Toyota Prius. While driving approximately between 10 to 20 mph on an uneven road surface; proceeding to a complete stop and applying pressure to the brake pedal, was followed by a no power response. Suddenly, the vehicle resumed normal operation within a few seconds. The failure continued to occur intermittently whenever encountering an uneven road surface or pothole. The vehicle has not been inspected for the malfunction. The failure mileage was 300. Updated 02/26/10 the consumer stated she was satisfied that the complaint described the problem she reported. Updated 04/29/10.

- San Antonio , TX, USA

I have a 2010 Prius purchased in late July 2009. I have definitely had problems with the braking system in winter weather on slippery surfaces. When braking, it feels like the antilock brake system fails and the wheels lock up momentarily. I don't let my wife or kids drive the car in slippery conditions. This is definitely an issue for me and I believe it should be investigated and pursued. I have contacted the dealer - alderman's Toyota of rutland, vt about the issue. They are aware of the problem.

- Huntington, VT, USA

When applying the brakes on my 2010 Prius, there is a surge in the car when it hit a manhole cover (bump). This happened under 20 mph on gentle brake application. Upon pushing on the pedal further, the car resumed braking and stopped. This "surge" lasted only a fraction of a second but was very disturbing and should not occur.

- Frankfort, IL, USA

Braking on rough surface results in car jumping forward and then eventually stopping.

- Rutherford, NJ, USA

2010 Toyota Prius - sometimes when braking the car has a power surge and you start moving faster.

- Plymouth, MA, USA

We purchased new 2010 Prius at the end of last September in 2009. Both of us have had the experience of "losing control" of the car while braking on icy roads. My first experience happened during our first big snow fall. I was approaching the entrance ramp to an express way and had to apply the breaks when a car infront of me began to slow down and slide to the left side of the ramp. As I applied the breaks, the car began a series of quick forward jerks associated with knocking sounds. I also heard a slight change in how the engine sounded. Fortunately, I escaped a traffic accident since my Prius drifted to the right before control was reestablished. It was frightening. This is the first car I have owned that has an anti lock braking system. I assumed that is why I experienced the loss of control and why it felt so uncomfortable. When I told the dealership about it, I was advised to take the car to an open area and practice using the brakes in order to get used to it. Since then, my husband has had the same experience while trying to stop the car on icy roads. He tells me that the "jerking" and the knocking sound is not part of a normal anti lock breaking system. This is why I am reporting our experience to the U.S. National Highway Traffic Safety Administration. Thank you.

- Middleton, WI, USA

Momentary loss of braking while in at low speed (about 8 mph) on uneven road surface or wet conditions resulting in a surge forward. When in a turn, maintaining control of the vehicle can be challenging. Condition is replicable, I.e., I can reproduce the braking loss/surge at the same place in the same conditions, at any time.

- San Antonio, TX, USA

Problem is onset of acceleration when brakes applied in 2010 Prius 4, purchased at antwerpen Toyota, clarksville, md in August 2010. Problem has been detected 2 times, without accident, but with significant increase in anxiety. Both incidents were approaching a stop sign, and seemed to be related to change in acceleration due to rapid braking. First incident in September 2009 was considered a 'driver issue' since I had owned the Prius only 1 month. However, second incident in November 2009 was clearly not a driver issue, and was initiated the same way--stopping at a stop sign after driving at highway speeds for some time. Neither incident involved a traffic accident.

- Laurel, MD, USA

On Wednesday, Feb. 5, 2010, driving a 2010 Prius on a Michigan road at 25 mph, some ice or freeze over, approximately 9:30am. I approached the stop sign and there was no brake engagement, no sound or feel of an antilock brake system. I couldn't stop the car, so I had to proceed thru the stop intersection. There wasn't an accident since there wasn't a car crossing the intersection.

- Bay City, MI, USA

I bought a 2010 Prius in late December and about two weeks ago, I was driving on a local street, which had some potholes on it. I could see a pothole ahead of me. Another car was coming from the opposite direction, which prohibited me from avoiding the pothole. I therefore braked slowly and came almost to a full stop as I went over the pothole. My foot was on the brake during this entire episode, but as I went over the pothole, the car suddenly accelerated. Although I did not have an accident or hit anything, the reaction of the car was very unusual. Since then, there have been some occasions when I have been at a light or stop sign with my foot on the brake and it has felt as if the car were about to move ahead, despite my foot being on the brake; it has felt like I needed to apply more pressure than normal to the brake in order for the brake mechanism to work properly.

- Oakland, CA, USA

I live in the phoenix, AZ area. While driving my 2010 Prius, when I go over an abrupt bump with brakes engaged braking completely fails momentarily. First few times this happened I thought maybe my foot had reduced pressure on the petal due to the bump but later confirmed that this is not the case. It occurs almost daily - every time I go over an abrupt bump with brakes engaged. I have a daily drive that takes me over some slightly rough pavement as I approach a stop light. Nothing has been done to correct the problem - I am just aware of it and am careful to account for that occurrence as I approach the light.

- Gilbert, AZ, USA

I drive a 2010 Toyota Prius and have experienced braking problems while braking and going over bumps/rough pavement. I have 6000 miles on my car and have had this happen about 5 times. During one occasion, while slowing for stopped traffic, I drove over a bump, and I felt the break pedal vibrate like the antilock brakes were being activated, then a quick "release sensation", during which I had no brakes, like I hit a patch of ice. I was just able to avoid hitting the car in front of me by swerving into an open drive way. I was also with my wife as a passenger in this car and she had a similar event while braking and hitting a bump in the road. This is not acceptible.

- Seminole, FL, USA

TL- the contact owns a 2010 Toyota Prius. Whenever the contact drives the vehicle at any speed and travels over and bump or a pot hole the contact noticed that the brakes will momentarily disengage and then return to normal. The vehicle has not been diagnosed and the contact has noticed the failure since the day the vehicle was purchased. The current and failure mileages were 5500. Bml

- Newton, MA, USA