Snow driving my new Prius

Good tires don't seem so expensive now, do they?

Apparently, the new generation Prius has improved snow performance. I'm not sure what the changes are, exactly, but it sounds like this issue has been noted and addressed.

 

I agree with your assessment that traction control on the Prius is sub-optimal. The traction control protects the HSD, but doesn't improve traction, and in some cases makes a bad situation worse.

I do have to quibble with your description of your close call with death. You state: "But as I was half way up, my car stopped. I didn't know what was happening. Then my car started sliding backwards out of control. It turned and lodged into a snow bank instead of going over the cliff."

Once your car started sliding backward, traction control was out of the picture. This backward slide indicates that the driving conditions were inadequate for your tires. Even four wheel drive would not have helped in that situation. If four locked tires are insufficient to keep your car from sliding, no amount of traction control will ever help.

It's not a great system, but let's not blame it when it's not deserved.

Tom

 

Traction control uses both the throttle to reduce engine torque and applies brake force using the ABS system in opposite to the spinning wheel depends on the severity of the spinning wheels.

Can someone explain how the TRAC traction control system works? - Toyota Forums :: Toyota Nation

 

Sorry, but this is plain wrong with the Prius. The Prius traction control system only controls power to the drive wheels. At no time does it engage any of the brakes.

The differential braking system that you describe is used on more sophisticated traction control systems, such as the one on the Toyota FJ40.

Tom

 

You have to have snow tires to drive in that kind of snow--with any car, including those 4WD SUVs.

 

It's difficult for you to make this assessment since you weren't there. You're speculating. My friend had just driven up the road in a front wheel drive older Toyota.

You also might not have seen the part where I said I would have made it up the hill in my old Camry. Why the car started sliding backwards, I'm not sure. Probably it had to do with the fact that I had the horrible OEM tires on the car and I had just lost momentum. By trying to move the car forward, I may have weakened the friction that four stable (ie: not spinning) tires might have had on the road.

I've gotten stuck on several other slippery hills, mostly snow and ice, but once or twice gravel. Several others on PC have also said they've been put in life threatening situations when TC brought the wheels to a full stop.

I don't think my criticism of the Prius's traction control is exaggerated or unfair. It seems that this is the worst flaw on the car because it puts passengers' lives at risk. As a result, TC deserves all the criticism we can give it.

I was told by Toyota that they read these posts and take them into account when upgrading cars. The 3rd gen Prius has vertical seat height adjustment. I bet complaints on PC about the lack of height adjustment on the 2nd gen Prius played a role in this.

Hopefully the numerous complaints about TC over the years on PC will play a role in upgrading the TC on the 3rd gen.

 

No, I don't need to have been there, assuming your description is accurate. I don't dispute that your friend went up in his two wheel drive, nor can I say that you wouldn't have made it in the Camry (I did read your OP). You had four stable, non-spinning tires once you pressed the brakes (you did press the brakes, I assume, otherwise the back slide would be no mystery.) If you couldn't stop with those, you certainly couldn't power up the hill. It's simple physics. OEM tires are the real answer to this puzzle, not traction control.

Tom

 

nyprius, get proper winter tires (not all-season).

 

I pressed the brakes after the car started sliding backwards. Before that, I was pressing the gas trying to go up the hill. Once the car was sliding backwards, pressing the brakes did not stop it. It was a slippery hill, but if I hadn't lost momentum, I would have made it up.

The problem was caused by TC bringing the wheels to a full stop while I was trying to go up a hill. That is a major flaw. It should not happen. It does not happen on other TC's that I'm aware of.

I wrote a long post called "Tire Upgrade". In it, I described my search for new tires. The search was prompted by this incident. I got great all season tires (Tripletreds) which are much better than the OEMS. But even with them, I've gotten stuck on slippery hills due to the Prius's flawed TC. I don't drive on bad roads enough to warrant getting snow tires. I've never needed them before. I've been driving for over 30 years. I have enough experience to know that the problems I have in the snow with the Prius relate mostly to poor TC, not tires. If the problem was tires, I would have had similar problems in the past.

The point I'm making here is that the Prius's TC puts drivers in life threatening situations. That's not an opinion. It's based on experience. If you search PC, you'll see many other Prius owners who have had the same life threatening experiences due to the faulty TC.

 

Obviously this varies from car to car and I haven't figured out a real pattern to it. I've been driving my 2006 pkg 1 Prius on OEM Integrities for 3 winters now, and with 26K miles on the tires, they still work fine. I also have plenty of winter driving experience, and my Prius drives as well or better than other FWD cars I've had. No need for other tires. They're probably a little slipperier now than when new.

They might have changed the TC programming at some point, or maybe for some packages (those also with VSC, for instance)? Based on bad experiences reported on PriusChat, I've deliberately tested my car on the steepest slopes I could find with several inches of wet snow. If I stopped halfway up and restarted, then I had problems, as expected. I could feel the tires spin and grip, spin and grip, even though essentially no forward progress was made. But in those conditions, no other 2WD car could be expected to do better.

I did have another experience this winter where I was at a dead stop facing uphill, unaware I was on ice. Starting off, I got nowhere, but the tires were spinning somewhat (speedometer varied between 5 and 12 mph). Eventually, by turning the wheels, I got off the ice and could continue normally. This was on a hill that had been previously blocked by the police because cars were having trouble making it up. The police left after rush hour, but apparently the situation hadn't noticeably improved.

So in my experience, the TC is fine and appropriate. (And I have been in upstate NY, I know a little of what you see. My sister used to live not far from Tug Hill). Obviously this is a case where YMMV.

 

My 2008 with pkg 6 has, so far, proven to be excellent in the snow. I was pleasantly surprised after reading the posts about the problems with traction control.
I have Nokian Hakka R tires on my car. I am an avid supporter of Nokian tires they are simply 'the best' in the snow. Without snow tires I can imagine this car, or likely a lot of front wheel drive vehichles, would be spinning away at stop signs and red lights and slight inclines in any kind of appreciable snow.
Snow tires are really the answer.

Also, I really like the VSC, it keeps that car going straight, the whole set up feels really safe!

Enjoy the rest of the winter, actually spring is not that far off.

 

I think the variation has more to do with conditions than with cars. If you were in some of the situations I and others on PC were in, you might have gotten stuck too.

If you voluntarily stop a front wheel drive car on a steep slippery hill, it might not get going again. The difference between the Prius and other cars is that it forces you to stop on slippery hills sometimes. In other words, the Prius involuntarily stops the car because TC brings the wheels to a full stop when it senses slippage.

Better tires obviously help. But that is irrelevant to the main point I'm making, which is that wheels should not come to a full stop when proceeding up a slippery hill. The fact that the Prius's TC does this is a major, life threatening flaw.

When other's say that they haven't had this problem, it doesn't mean the problem doesn't exist. It probably means they haven't been in the same situations as those that did get stuck or they had better tires.

Bottom line: The TC is flawed and should be fixed.

I had several conversations with Toyota officials about the lack of seat height adjustment and flawed TC. They got lots of negative feedback about these issues. The 3rd gen Prius has seat height adjustment. Someone on PC said they thought the 3rd gen had better TC as well. I hope so. TC should be limited slip, not full stop.

 

Bummer, they really look nice.

 

I don't think any of us will argue with you that the traction control on the Prius is a problem. The main argument you will get is that many drivers blame traction control when lack of traction is really the issue. Let me state again, clearly and concisely so there is no misunderstanding, I agree with your central point that traction control on the Prius is sub-optimal and sometimes a hindrance to driving.

Here is where you will get an argument from me (and you already have): traction control cannot make up for a lack of traction (differential braking can help, assuming there is some traction, but the Prius lacks this mode). If you try to drive in conditions where your tires have no grip you will not move, regardless of traction control, unless it is to slide backward down a hill or into a ditch. Many posters come onto PC and made statements such as "Traction control almost killed me!" when in fact it was lousy tires that almost got them killed.

Traction control gets blamed because it kicks in when the tires slip. While this is a fact, you cannot logically extrapolate the converse, or in other words, if traction control had not kicked in, I would not have slipped. Disabling traction control does not guarantee that you can drive up a slippery hill. Many Prius owners don't get this simple fact.

So here is what happens: You get your new Prius, complete with crappy OEM Goodyear Integrity tires, and try to pull out in front of a truck on icy roads. Traction control kicks in and cuts the power, nearly getting you killed. Let's look at this same situation without traction control - same tires: You try and pull out in front of a truck on icy roads. Lacking traction control, the drive wheels spin and you don't go anywhere, nearly getting you killed. It's the same outcome. The problem is the tires.

There are situations where spinning tires help. Gravel roads are one. Sometimes spinning works on light ice, where the tires will burn down to a better surface. Prius traction control is a definite problem in these situations.

As for the situation you describe on the hill, with or without traction control you were in trouble. Your description clearly indicates that the tires had no grip on the road. Either the traction control cuts power or you sit and spin. Either way you were in trouble.

Tom

 

Assuming you actually had any traction at all, I have been in those conditions and not gotten stuck. I enjoy driving in snow (when there's no traffic) so I've done a number of tests. I deliberately stopped halfway up the main hill in my tests because my car was simply not failing otherwise. I had to raise the ante in my testing. Yes it had troubles getting up the long hill with slippery snow, but it was no worse than any other FWD car.

That has not happened in my experience.

Or that the problem doesn't exist in all variations of the Prius. Can you get that in your head??

When the car stalls out because of TC, what do you see on the speedometer? Are the tires still trying to turn at all?

I do agree that changing the tires should not be the recommended course of action for safe driving for the average consumer. But if you live in an unusual enough situation (such as hilly, snowy areas) that 99.5% of the population doesn't see, it might be wise to change your tires anyway, just as on any other car a person in that situation could buy.

 

It is relevant.

Snow tires will slip less, and the traction control won't be as invasive. Your car will proceed forward.

Get snow tires.

 

The point I'm making is very simple: All other things being equal, the Prius traction control sometimes causes the Prius to stop on slippery hills. Better TC or no TC often would prevent this.

Of course better tires would reduce this problem. But that's a separate issue. TC should not bring the wheels to a full stop. Period. Other TC's do not do this. I don't know how to be any clearer than that.

Better tires can overcome the problem in many cases. But that does not mean that the TC should not be improved.

In the situation I described, my car probably would have made it up the hill if it were not for the TC.

That's it. Plain and simple. The Prius TC puts driver's lives at risk and should be improved.

 

You're missing my very simple point. TC should be improved. Period.

 

To bad they don't have an on command all wheel drive version. 4 wheel disks with the same set up in the front for regen in the rear. Use the rear regen when wheels are free rolling and not locked in.

 

Your experience doesn't invalidate others' experience. Just because you didn't get stuck doesn't mean others didn't. You said you tested on a snowy hill. All snowy hills are not the same. What's the grade? What's the base under the snow? Going up one snowy hill doesn't mean you'll go up them all, or that others didn't get stuck on snowy hills because of the TC.

Re the getting it into my head, that's kind of rude. Do you have specific knowledge that the Prius TC was converted from full stop to limited slip sometime in the 04 to 09 model years? I've heard conjecture, but haven't seen any proof. I've also heard people with later model Prius's say they got stuck due to the TC bringing the wheels to a full stop.