Base Model 2006 PRious - NTSB Complaint Filed

Did the brakes work when she pressed the pedal to stop the car?

 

Very sorry to hear that your car was totaled, glad your spouse is OK.

What was the make/model and tread depth of the tires?

 

---------------------------------------------------------------------
REPLY:

I wonder if what you experienced is a variant of an event I posted during the winter. I have a Touring 08 with traction and stability controls. I have several anxiety-provoking moments when I tried to enter a medium-fast traffic neighborhood street from a stand-still tertiary road. The Prius would get into the 90 degree turn about half way, slip on some minimal ice and the wheels would just stop for what seemed an eternity, given that the traffic kept approaching the intersection.

 

Sorry to hear about this incident. We need more info how the driver reacted. It would be nice to see a pic of the hill.

If the driver continue to accelerate when the wheels are slipping, any FWD car would roll back down. If the brakes did not stop the car, I would say the hill is too steep or tires are worn out.

 

2006 model does not cut power. It allows wheel slippage up to 15 MPH. I made a video showing that if you can google it.

 

I don't think the Prius lets the wheels spin BACKWARDS when traction control turns on...

If your sliding, then its too slippery for your wheels.

 

.

 

Re: Base Model 2006 Prius - NTSB Complaint Filed

Looks like the OP did the best he could, by equipping the car with good tires. I'm wondering how fast the OP's wife was going when this happened.

Maybe her next vehicle should be a Jeep Wrangler with mud-terrain tires? :madgrin:

 

It is questionable how the snow tire supposed to perform in the loose gravel and mud.

Sliding backward should not total the car, just fender bumper sort of thing. This seems unfortunate accident. Did the car roll? Was there a deep ditch in the woods? If there were guard rails or fences, this would not happen.

My point is that the road and condition are not safe. The way the driver reacted can be a factor. It is not right to put the entire blame on the car.

Did your insurance cover the total loss?

 

Hi All,

This would be "Sudden Unitended Decelleration" ? Somewhat the opposite of what people are talking about.

Well, if the tires start slipping, they are now in the sliding friction regime. How they got there is the problem, once they start slipping, there is no control of the vehicle. Including sideways off the road.

Now, would dyanamical control methods (using the tires as reaction control jets to spit out debris) have recovered this situation? I think that might be hard to proove.

Allot of people seem to think that this does good, but I have always found that going to zero throttle in such siatuations is the only way to get out of the sliding friction regime, and gain more tractions.

Was she on a hill where this could not happen? That is, once sliding friction occured? There is always going to be one small time when the car transistions from forward to reverse velocities, when if there is no torque applied to the wheels just before the transition, that torque could be applied to stop the car and hold it. Unless the car was driven on to a surface where the traction was insuficient to hold the car stopped, on the slope.

All the answers to these questions seem to be very undertain. Is the fault with the car, the driver, or the roadway maintenance, engineering and control? If the car was at a greater speed when the slick spot was hit, and aimed parallel to the road, could the car have made it through - the case of the too timid, or inexperienced, or sloppy driver. Was there a curve too close to the slipery spot, making the neccassary speed to minimize needed wheel torque too dangerous? This is the case of roadway mainteinance, engineering and control - should the police have closed the road at that time, was the roadway covered with soapstone gravel, was the curve designed to be too close to the steep section? Were the tires at too low a pressure, and hydroplaned?

Hmm?

 

I had the identical problem heading up a mountain to an event
in the Berkshires, fairly close and similar terrain to the
Catskills ... took a good run at it a couple of times, but the
gravel road was just moist enough that the tires couldn't quite
get me over the steep part of the hill. The right course of
action is to feather the pedal back and apply just enough to
hold the car where it is and gingerly try going forward again;
if it's not gonna happen the wheels will spin just a little and
let the car slip back, at which point simply braking will lock
and hold. Then it's all ready for a safe back-down. The oops
was probably to keep mashing the go-pedal in the hope that it
would all work, but with the wheels trying to spin guess what
is lost -- *steering* ability.
.
I was heavy-loaded on this one and didn't want to take the tires
down to like 25 psi which would have helped, so we simply unloaded
some of the gear at the bottom, I made it up with the lighter
load, and then went back down for the rest. Later we tried the
tire trick in a friend's Prius who ran into the same thing [and
he had the Integrities on, so it was an even more interesting
test] ... let a bunch of air out of his fronts and the bigger,
squashier footprint allowed him to get over the hump. Then we
pumped 'em back up, since all he had to do thereafter was go down.
.
All these things have explanations and mitigating strategies
available, and one must weigh the value of safety complaints
vs. plain ole physics.
.
_H*

 

Ok, found the video I made 3 years ago. The power was not cut as the traction control light comes on and the speedometer shows the tires slipping.

I have 2006 Prius pkg 2. It does not come with VSC, just TC.

Prius Traction Control in snow

 

i have 2005 with all options. When on a hill and turning up on the hill with slick/wet conditions when pulling out the traction control comes on taking power off drive wheels. Traffic coming down hill almost t-bones me because of this "safety" feature. It seems that the safety devices can back fire on some occasions!

 

As pointed out above, all Prius have traction control.

While the traction control may have prevented your wife from climbing the hill, it had absolutely no bearing on her ability to stop. You can't expect to climb a hill that is so slippery that brakes won't hold, unless you have enough momentum to coast to the top. This situation is a classic example of bad road conditions.

Tom

 

Even with perfect friction between your tires and the gravel, there won't be perfect traction between the gravel and the gravel below it, or the slick mud below it. Maybe going up backwards would be better since more weight of the car is on the wheels more below the car. This may be rear-wheel-drive country.

 

Clearly this is the result of the lack of tank treads installed on your prius.

 

Really sorry to hear about your car!

I've come across one road where I had traction issues. It was a dirt/gravel road with a very steep hill. Initially, I went too slow and the traction control kicked in due to the wheels starting to slip, and I was stopped about 3/4 up the hill. I was able to safely back down the hill and attempt it again with a little more speed, and had no trouble overcoming the hill.

I later thought about the road, and realized that it really wasn't even a road one should expect a 2wd car to easily cope with. If there had been mud, I would have expected the hill to be off-limits. Muddy hills can be a problem even for 4wd vehicles, as you can still end up sliding off the road.

My other "car" is a Range Rover classic, which is full-time 4wd and is superb off-road. However, even with a vehicle like that, mud can pose problems. If the tire treads become completely impacted with mud, any vehicle will basically behave like it has bald, and very slick tires, which can cause all sorts of problems, especially on a hill.

I agree that the traction control can be awkward to deal with at times. And I can certainly see how it could cause problems with someone that's not very used to the car, as it definitely takes some getting used to.

The main difference is that with the Prius traction control, it can completely stop the vehicle, whereas with other cars, you'd be spinning your wheels, which makes you feel like you have more of a chance. But, wildly spinning wheels usually cause problems.

What did you have the tires inflated to? I have found that the traction control seems considerably more agreeable (less aggressive) with lower tire inflation, such as at, or slightly over the pressure specs on the door jam.