2010 Toyota Prius has a major flaw in the regenerative / hydraulic braking system. If the car is slowing gradually with regenerative braking active and the road surface changes due to a pothole, uneven/broken surface, or speed bump, the hydraulic braking is reengaged very slowly. This causes the car to appear to accelerate for a second or two until hydraulic braking is engaged by the car's computer or because the driver had to increase brake pedal pressure dramatically to slow/stop the car. I have been able to reproduce this daily on a number of the roads I consistently travel. Speed during these incidents is usually anywhere between 5 and 30 mph. One example: Driving on a road and coming to a stop light... slowing gradually on regen braking, then I hit a part of the road where there is an uneven surface. Regen braking stops and car coasts with no braking, sometimes for up to a second or two. This is a major concern as it could result in a car accident or pedestrian death. I have already had at least two near misses where I have had to slow or stop suddenly while braking in regen mode and the switch to hydraulic mode is severely delayed. This could have resulted in rear-ending a car in front of me. Issue has been observed since I first obtained the car in July 2009.

- East Haven, CT, USA

Toyota Prius 2010 failed to stop at stop sign. I got a brand new Toyota Prius 2010 in late October 2009. Most of the time the brakes have been very good however I noticed several times that when I press the brakes the car kept going for a good few seconds before it stops. Yesterday I was in a small local road with speed around 28 mile/hr. When approching the intersection, I pressed the brake but the car was not slow down, I kept pressing the brake very hard and it finally stopped but the car was into the intersection already. Thank god, there was nobody crossing the street. I googled Prius 2010 brake problem and found there were many same complaints out there and since dealers could not reproduce the defect, they can not offer a fix.

- Troy, MI, USA

My 2010 Toyota Prius under certain conditions will have a reduction in braking power. It will give the illusion of acceleration, but I believe the problem is a reduction in braking power. This problem has happened repeatedly and I frequently experience it in a location I regularly drive. As I approach a 4-way stop there is a bump that covers the width of my lane. As the front tires go over the bump the car feels like it start to take off just short of the stopping point. It quickly recovers and I am always able to stop, but the feelings is unnerving since it happens so close to the stopping point. I have contacted my Toyota dealer, but they say they have no reported problems and did not even take any information.

- Plainfield, IN, USA

When braking our 2010 Toyota Prius, the brakes sometimes release while the driver's foot is on the brake pedal. The driver needs to release the brake pedal and re-apply pressure for the brake to re-engage. The problem does not occur every day but it has occurred often enough that both drivers of our car have noticed this on several occasions during the six months that we have owned the car. It appears to occur more at speeds below 15 mph, on downhill slopes, in colder weather and on slippery roads. Given the circumstances, the problem tends to happen when approaching intersections, where most braking takes place, making it a more dangerous defect. We purchased the car at the end of July, 2009. We reported the problem to the Toyota dealership when the car was in for its first 5000 mile service in January, 2010. They road-tested the car but could not replicate our experience, so they could not diagnose the issue.

- Washington, DC, USA

While braking my 2010 Prius there are times where the car appears to surge forward. The initial braking occurs fine but near the point of coming to a complete stop (ie less than 10mph) is when the surge occurs. Initially I attributed this to icy road conditions but this has now occurred on dry pavement. The dash light indicating slippage of the car does not appear when this occurs. The problems seems to occur more often within the first 5 miles of starting the car. This surge does not occur everyday nor every time the car is started. It does not seem to be strictly temperature related although it has started occurring only in the winter (car purchased in July).

- Vicksburg, MI, USA

Brake problem when on uneven surface or hill, sometimes turning. Car hydroplanes and brakes do not work. Has happened at least a dozen times since buying the car last August. Three times have come close to hitting another car. Reported problem to dealership. Waiting to hear back.

- Radnor, PA, USA

I have a 2010 Prius and saw an article about there being possible brake problems with the model. I have had this problem probably about 6 times since I got the car last July and, when I mentioned it to the dealer, they said there wasn't anything wrong with the brakes when they ran the diagnostic. When it happens, I'm in the process of braking, and there's a "push", almost like the brakes didn't "take", followed by a loss of steering for a second or two. It's also happened to my husband one time. There doesn't seem to be any rhyme or reason as to when it happens (wet road vs. Dry road, turning or going straight, flat or hill). I originally associated the problem with the brakes because I also have the "sliding" icon come on the dashboard when I'm completely stopped and lean forward in my seatbelt. However, I'm now wondering if it's not the brakes, but the transmission, since it sort of feels like it's not downshifting when it's supposed to, or it shifts back into a higher gear for a second while braking. I came to this conclusion after waiting in the car while it was running. With the car on, emergency brake on, but not in park, there was a definite "jolt" when the gas engine would turn on and then off again a few minutes later. Although there hasn't been a crash yet, there were two times when it came really close to that, as I was turning and almost hit the cars on the side street that were in the left turn lane waiting to turn onto the street I had been traveling on.

- Cincinnati, OH, USA

When braking at low speeds, if the car hits a manhole cover or uneven, bumpy road, there is a split-second loss in braking (which feels like acceleration since the driver expects to be decelerating at the time). Other priuschat site users have complained about the same problem with the 2010 Prius - some users claimed this was "normal" when the regenerative brakes switch over to hydraulic brakes and that there was really no loss in braking. It may be "normal" but it's scary as heck when it happens and if a pedestrian crosses in front of the car or a car in front of a 2010 Prius stops quickly under just the wrong circumstances, I suspect an accident would result.

- Crown Point, IN, USA

2010 Toyota Prius brake problem. Brakes do not work properly particularly in snowy day.

- Franklin, WI, USA

The contact owns a 2010 Toyota Prius. The contact stated that the brakes failed when driving over uneven pavement at low speeds. The contact also stated the vehicle lurched forward when braking under normal road conditions. The failure happens when driving over a speed bump or a pot hole. The vehicle was taken to the dealer and the contact was told to remove the floor mats but the problem persisted.the contact stated that the dealer was unable to duplicate the failure because it happens randomly. The manufacturer was contacted but the contact did not receive an acceptable answer from them. The failure mileage was 8,362.

- Garrettsville, MD, USA

On Thursday, January 28th my wife drove our 2010 Toyota Prius to work. The was a slight coating of snow on the ground. Less that one block from our house, driving at no more than 10-15 mph she applied the brakes to stop at a stop sign. She reported that the brakes seemed to lock (not the normal ABS feel) and she lost control of the car, which then slid/skidded into a curb which punctured the front passenger tire. The car appeared to have only a punctured tire which was changed by a aaa service truck. After the tire was changed and the service truck left, I attempted to drive the vehicle to a nearby tire dealer. As I tried to drive the car, I heard and felt a loud scraping noise that sound and felt like the brakes were still engaged. Even though I was now on clear pavement if I at all tried to apply the brakes, the ABS went on, but in an aggressive manner. The ABS also went on a couple of times even without me putting my foot on the brakes. The tire dealer said he thought we might have been the frame and told us not to drive the car. The car was towed to a nearby body shop to be inspected by our insurance company, state farm. As of February 2, 2010 no inspection has taken place. It is our contention that something malfunctioned with the brakes which caused the accident.

- Peekskill, NY, USA

Brake on my Toyota Prius 2010. A few month ago, I was driving on a street with many potholes in san francisco. I was coming to a stop on a red light. I applied the brake to slow my Prius. As I was applying the brake, the car's front wheel hit a pothole. I suddenly feel a total lose to brake on the car for a slight second as the car seem like/feel like surge ahead. A fraction of second later, the brake went back to normal. It was a very scary feeling. I did feeling unsafe. I talked to the master mechanic in the Toyota dealer. He said the it is normal as the ABS kick in when the car hit the pothole. It is doing it job. However, I had driven more than 5 cars with ABS and vsc and never have the kind of issue. This only happen once.

- San Francisco, CA, USA

My 2010 Toyota Prius has a serious braking problem, the car lunges forward after apply my brakes over a bumpy surface. This is very unexpected and luckily no one was in front of me otherwise I would have hit them. This already happened several times, took my car to the dealer and no solution, I don't know what to do with a brand new like this.

- San Jose, CA, USA

I had my new Toyota Prius about 4 days. On Saturday morning, 1/23/10, I was backing out of my driveway. There was ice, but when I gently put on my brakes, I felt nothing. Two seconds later after sliding to the end of my driveway, the brakes caught. I was concerned that the feeling was quite odd, but chalked it up to the ice. Then the next morning, it happened again when there was no ice, but wet roads, first coming to one stop light and then about 15 minutes later at another stop light. The same feeling--putting on the brakes and hitting air--then 2 seconds later the brakes grabbed. I immediately drove it to the dealership and left it, citing brake failure. They had it about 2 days and no one believed me. Said it was fine. Yesterday, 2/1/10, and again today, 2/2/10, it did it again to and from work. I do not feel safe in that car. Something is wrong with the brakes.

- Bloomington, MN, USA

When backing up the 2010 Prius, the brakes grab. I release the brake pedal and reapply and each time the brakes grab.

- Leesburg, FL, USA

I have been driving my 2010 Prius for 6 months and have experienced the following nearly 10 times: When braking, if a pothole or bump in the road is hit, the car seemingly jerks forward/accelerates for a split second. This results in less control over where the car comes to a complete stop. The most unnerving instances of this occur when approaching the end of a road or a crosswalk. I nearly hit a child because of this unpredictable reaction to a pothole. Also, the brakes are less effective in snow than any other car I've ever driven. No matter how slow I'm going or how hard I hit the brakes, I've found that I'm guaranteed to skid several feet, oftentimes into intersections/traffic. Perhaps unrelated to the pothole issue, but maybe not. Both issues are extremely dangerous.

- Cambridge, MA, USA

While braking if I hit potholes the car speeds up from loss of braking action even thou I am still pushing on the brake pedal. I have to quickly let up and apply brakes again to stop vehicle. Has happened three times now, twice in the last two days. First time thought it was my imagination, but now I know that I was pushing on the pedal and the car just took off until I reapplied the brakes.

- Omaha, NE, USA

The contact owns a 2010 Toyota Prius. The contact stated that the brake failed to engage when he drove approximately 25 mph on rough road surfaces. The dealer stated that the ABS engaged and that was a normal brake function. The failure occurred several times intermittently. The Toyota manufacturer has not been contacted. The failure mileage was 46,000.

- Croton On Hudson, NY, USA

This is a complaint about a recurring event that has serious implications in the wrong situations. For five times now, since driving our new car, our brakes have released after going over a bump in the road. This bump can be as small as a crack caused by a nearby tree's roots, or larger like a pothole. It has also occurred when driving over slick sewer covers. It typically happens when braking, then hitting the bump, then brakes release, and the car is no longer breaking. This is especially dangerous in hilly cities like san francisco, where if this happens going downhill, the acceleration accompanied by the lack of braking going downhill can result in crashing into the next car, or worse, hitting a crossing pedestrian at a cross walk.

- San Francisco, CA, USA

My 2010 Toyota Prius brakes fail ( disengage or release) when braking on icy surface or while braking and a bump or pot hole is hit. I fist noticed this issue on Dec. 19, 2009 after a snow storm but it continues to happen even on dry road when a small bump is hit. I reported it to Toyota and they told me they could not find any issues with the brakes. Nothing was done to correct the problem. The car actually goes faster when you hit a bump while braking. The brakes release and it feels like you have no brakes at all for a few seconds. This is not right! it happens very unexpectedly and you can not judge your braking time correctly. It happened to me recently when stopping at stop sign before entering a cross road. I hit a patch of rough road and it drove me to stop passed the stop sign and was lucky there were no on coming traffic.

- Nesconset, NY, USA