Got into an accident today due to brake problem =(

http://priuschat.com/forums/gen-iii...-discussion/77192-car-slips-when-braking.html


I made this post 3-3-10


http://en.wikipedia.org/wiki/Heaven's_Gate_(religious_group))

 

again, i have to ask...why do 99% of Prius drivers over a period of 10 years have a stellar no-accident record? Yes, I'm being snide. and smug. Jesus, if the car doesn't work for u, sell it and go back to a "regular" car. Or for other's sake, just slow down when road conditions are suspect. not just weather related. it's not a super car.

I got into a fender bender because i was not paying attention to my following distance. by brakes engaged after my brain...must be the vehicle. I'll sue and screw the rest of the world that can drive attentively.

 

You are partially right:
The 'problem' is not the ABS (which itself can make stopping distance longer - but you are still able to steer, which is even more important).


I will try to explain what is happening:

I am sure you experienced what happens if you want to accelerate and one (only one) wheel is on ice - exactly nothing (without traction control). One wheel is spinning on ice, the other one not moving at all. This is because of the differential. It is important to make it possible for the wheels to rotate at different speed when making a curve (the outer wheel has a longer distance to travel).

When recuperating, you are not using regular brakes, just your engine is used as a generator. The differential is working as before: If one wheel is on a slippery surface or losing ground contact on rough roads it will start spinning faster while the other wheel cannot decelerate the car anymore.

Now it takes a split second for the regular brakes to kick in. During this time you feel the 'lurching forward' which actually means 'less braking power'.

As it happens only while the car is recuperating the braking power is not very strong. If you need to stop quickly, you always should step harder on your brakes. The Prius will use regenerative braking and regular brakes together. There is no possibility of the 'lurching forward' feeling as the regular brakes are already engaged.

If a driver is not able to push the brake pedal when he wants to stop he should reconsider if he should be driving at all.

Greetings
Martin

P.S.: You will not feel the vibrating brake pedal in the Prius even during ABS use, as the Prius is 'drive (and brake) by wire'.

 

The driver will not be able to press the regular brakes because it is to late because they tailgate or brake too late.

 

So if you bought a Prius in February 2010, then the dealership should have fixed the brake problem? Would you say it's a problem if the dealership not only did not fix the car, but also failed to notify the buyer?


(It's just a theoretical question - not that this would ever happen, nor lead to any problem)

 

I didn't realize that being a member of this forum since November of 2009 (date I purchased the car) and only making 4 previous posts makes me a "newbie" and therefore somehow not qualified to respond to someone's post about a similar experience with my Prius.

I have had the brake recall performed. I still have the same issue as before -- a momentary loss in braking while driving over rough surfaces, potholes, manhole covers, etc. It has not caused an accident, but I personally do not feel comfortable with the regenerative braking "feel".

It is my personal opinion that I should not have to "accept" this as normal in a hybrid vehicle. I would rather get 38 mpg and have confidence in the "feel" of my hydraulic brakes, than to get 48 mpg and not. Your mileage may vary as well as your opinions. I guess I am not "cut-out" to be a tree-hugger after all.

However, this does not make me an idiot or a poor driver or a maniac who is driving too fast on an off-ramp. I drove my Tundra the exact same way before I traded it in on a Prius and NEVER felt what I am feeling now. The issue is real. Some choose to accept it and others do not.

Feel free to flame away as I am obviously just a "newbie" who is coming out of the woodwork to respond to this issue.

Troy

 

I don't think it's the dealer's responsibility (by law) to notify buyers of recalls. It's the manufacturer's responsibility. IIRC, Toyota went out of their way to have the dealers reach out during the sticky accelerator campaign that didn't affect Priuses.

From a quick look at one document (don't have time now) from NHTSA ODI - Recalls Documents, http://nhthqnwws111.odi.nhtsa.dot.g...is/Public/Recalls/2010/V/RCMN-10V039-3775.pdf says

 

The FFH TSB and "Customer Satisfaction" recall were due to a glitch that caused excessive sensing of a computer failure that deactivated the regen braking creating a startling condition requiring the pedal to be pushed another inch down for fully functioning friction brakes. This was accompanied by a chime and dash warning and was only reset by cycling the car on and off. This was a rare malfunction that was not normal operation. The software repair supposedly made the fault detection less sensitive. The FFH community has not reported the type of ABS/Stability braking behavior mentioned here.

 

I do not know but I think the "customer satisfaction" issue with the Fusion/Milan Hybrids sounded a whole lot scarier... it sounds like they would have ended up 25 feet into oncoming traffic!

 

I've experienced the problem and ate a snowbank at the end of my driveway because of it. It'll never happen again because I know how to compensate for it NOW. It might have been nice to be warned that under certain circumstances this might not be the case however.
Simply put, the Prius does NOT brake like a normal car. Of course under MOST circumstances it feels just like a normal car. Its been programmed to feel and respond like a normal car. That is until it doesn't. Then it's a shocker and you don't know what to do.
In my case the road was Icy and bumpy and downhill. I live on a dirt road, it gets that way in the winter. ABS was engaged and I was steering it (under ABS) into the driveway just like any other car. The left tire went over the lip of the driveway and all of a sudden it felt like I had no brakes. I think maybe it got confused and switched back to regen for a moment or something? No idea. I didn't put more pressure on the brake or let up or anything because in normal ABS it would do no good. What it came down to was that the 1/2 second or whatever it was was just enough time for it to break traction and start sliding laterally. Once that happened it was all over. It did NOT behave like any other vehicle I've ever owned before including my Tacoma pickup.
After that I made a point of playing with it (in a safer location) and discovered through experimentation that if I let up on the brake and re-engaged, that it kicks back in. I also learned that I could not trust it to remain predictable when the ABS engaged. Now I treat it like a non-ABS car from the olden days and I'm fine. It's just a shock the first time it doesn't behave like a normal car, that's where I and I'm sure others get into trouble.
I wish Toyota would have let me know that while it feels like a normal car most of the time, it may not behave like a normal car under extreme conditions and that you should give it some extra space.

 

Totally understand what you are saying here.

After the first test drive of the car I told myself this is not like any other car (not in a bad way, just different) and as such I wouldn't take anything for granted. Even today, almost a year later, I leave plenty of space between me and the other guy, much to the dismay of others behind me.

 

Is this the intersection?
[ame=http://maps.google.com/maps?f=q&source=s_q&hl=en&geocode=&q=Oso+Parkway,+California&sll=33.598893,-117.644005&sspn=0.078068,0.132866&ie=UTF8&hq=&hnear=Oso+Pkwy,+Orange,+California&ll=33.580656,-117.672734&spn=0,0.003098&z=19&layer=c&cbll=33.580574,-117.672701&panoid=ZPsz-ySubxJE7lAKdQayFA&cbp=13,168.38,,0,-7.23]Oso Parkway, California - Google Maps[/ame]

I followed the S. bound I-5 exit to OSO.

Thanks,
Bob Wilson

 

That's like saying you should purposely to spin the car to get used to the stability control. Does anyone do it? No

 

In 10,700 miles driving my 2009 Prius, I have never experienced any strange response while braking. (car has 10.7k miles total).

Is this apparent problem showing up only in the 2010 or have Gen2 owner's experienced it also?

I suppose I'll need to rent a 2010 Prius a 6th time and more 'n try to get some type of unusual braking response as I haven't experienced any yet. Guess I'm not trying hard enough.

 

If you're talking about the brake pause while lightly braking and going over manhole covers or some cases of uneven pavement (usually/always? accompanied by flashing yellow skid light), it's been known since the 1st gen. I've hit at # of times on my 2nd gen and have a consistent repro spot at http://priuschat.com/forums/gen-iii...99-poll-prius-brakes-problem.html#post1031776.

My answer in Bob's poll was:

I along w/MANY 2nd gen owners feel it's no big deal on our cars. I can't speak to the difference on 3rd gens, if any, before or after SSC-AOB due to insufficient seat time.

 

Err. Yes!

Also, in some countries, controlling a skid is part of the driving test!

 

I would exactly call it brake dropout, and it ONLY happens when you're braking lightly, using regen only. If i brake hard over the -same- terrain, it doesn't happen.

The equipment i'm using is my eyes, ears, and bum dyno.

 

Had my Prius for three weeks and have not noticed anything unusual about the brakes.

Can any of you experienced Prius drivers post a clear statement of how the brakes should be used? I know you've probably done so in this thread and elsewhere, but can you please do so again for us new owners? Many thanks.