Last post on Aug 21, 2013 at 5:16 PM
You are in the Toyota Sequoia
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Toyota Sequoia, Toyota Highlander, Toyota 4Runner, Toyota Land Cruiser, Toyota RAV4, Toyota Tacoma, Truck, SUV
#1623 of 2493 4WD and VSC on Very Wet Roads
Nov 06, 2004 (2:50 pm)
I just totaled my 2001 4Runner due to a highway-speed accident on a wet road surface. Although by definition I was going too fast since I lost control of the SUV, I'm wondering whether I should have made different choices of 4WD/VSC, given the road conditions, that would possibly have helped me recover control of the vehicle instead of spinning out of control.
Due to the rain, I had engaged 4WD Hi. My VSC was on. The center differential definitely was not locked.
While going down a moderate grade on an interstate with a light rain but a very wet road, my 4Runner's rear began swinging out counterclockwise. I believe I lifted my foot from the accelerator (although it's possible that I didn't change my accelerator pedal position; it's hard to remember) and turned the front wheels into the spin (i.e., to the right).
Basically, the 4Runner just kept rotating around - turning into the spin did absolutely nothing. After spinning 3/4 around the rear of the vehicle slammed into the concrete center divide, I did another full rotation so that the rear hit the divide again, and I ended up nearly facing forward again as I stopped. Thank God I was not harmed in any way in this high-speed accident.
I used to drive in snow and ice conditions as a matter of course and I've successfully recovered more than once from my vehicle's rear swinging out by turning into the spin exactly as I did in my accident. However, I was in a FWD vehicle in those other instances and it did not have VSC.
Did my being in 4WD with VSC engaged help or hurt my recovery efforts in this accident? Looking at some of the earlier postings that describe braking being applied to up to three wheels in slippery conditions has me wondering...
Thanks for your insight. Thanks also to Toyota for making a vehicle in which I crashed so hard that my driver's seatback was bent backwards by the force of my body against it, but in which I was otherwise so protected that I walked away with only a few sore muscles.
#1624 of 2493 Sounds like.....
Nov 06, 2004 (6:34 pm)
cruise control was on.....??
Or else the e-throttle(??) and/or VSC wasn't very quick in shutting down the engine...
Or the VSC malfunctioned and after initially applying the right front brake to counteract the inital "spin" and then it never released it.
#1625 of 2493 Sounds like
Nov 07, 2004 (12:47 am)
he's plain too fast. No VSC or 10 wheel drive will save you if you go 70 mph try to turn too sharp. You have no traction Wet road or dry road. 4500 pounds is a lot of momentum.
#1626 of 2493 Re: Sounds like..... [wwest]
Nov 07, 2004 (9:18 am)
Cruise was not on; never in potentially slippery conditions. I have no sense of whether VSC actually did anything wrt throttle or braking. I don't remember the engine doing anything "on its own."
#1627 of 2493 Re: Sounds like [stove1]
Nov 07, 2004 (9:26 am)
I agree that, by definition (since I crashed), I was going too fast. Of course, up to that point I had been driving with the vehicle fully under control so I suspect I hit a portion of the highway where the water was a little thicker on the road.
I want to correct any notion that I was attempting a turn at highway speed. I was driving straight when the rear end drifted out to my right. The only turning I did was in response to the spin to try to recover control.
I don't believe vehicle safety systems should compensate for every driver error, such as going to fast, but I would like to understand why, when I tried what had always worked previously, it didn't work this time. Thanks.
#1628 of 2493 Re: Sounds like [between4rnrs]
Nov 07, 2004 (10:01 am)
We're just glad you came out of it unharmed!
#1629 of 2493 Sounds like
Nov 07, 2004 (11:30 am)
sorry about my wrong assumption. (turn)
4500 pound is a lot of weight, maybe your FWD cars are much less. SUVs have a tendency to roll, your wheels may have left ground. Coupled with wet road no traction on maybe all 4 wheels. Too much for the VSC.
#1630 of 2493 VSC failure....??
Nov 07, 2004 (4:52 pm)
#1631 of 2493 4WD and VSC on wet roads
Nov 07, 2004 (8:41 pm)
between4rnrs, thanks for the interesting post. I'm happy to hear you're not seriously injured. I've experimented with the VSC, ABS, and brake-assist on slick roads, and here's what I think: You got into a very slick patch where you had VERY low traction (hydroplaning, something on the road, etc.) and there was simply nothing the system could do. It's designed to make the most of available traction, but sometimes that isn't enough. Once you got the spin (vehicle rotation) started, there was insufficient traction to stop it.
I think your choice of drivetrain modes and actions in the incident were correct. Maybe braking would have helped, but I suspect not. In previous vehicles I've very occasionally encountered a sudden patch (usually ice or polished snow) of near-zero-friction and even on the flat there was little I could do. In these cases my car began to spin, and only a combination of luck and eventual traction (and just a little skill) saved me from big problems. You do't have to do anything (such as braking or turning) to cause the spin if conditions are slippery enough, and the failure of the system plus your wheel turning to stop the spin would suggest that things really were slippery, at least for a brief time.
There are other possibilities, though. The system should have at least been blinking its yellow dash light at you, and probably beeping to indicate it had lost control. You didn't mention anything like that. Perhaps there was indeed a VSC malfunction.
The system should have been braking the right side wheels (I don't know the precise combination or balance), but you might not have noticed in all the excitement. I've experienced the right-side-only braking and it wasn't terribly dramatic.
The de-throttling and throttle response is instant in my experience, so I don't think that was it.
We can all make mistakes from time to time, no matter how careful we are, but sometimes stuff just happens that's outside all reasonable bounds of caution.
#1632 of 2493 Thats hard...
Nov 08, 2004 (12:47 pm)
First of all Im glad you are OK, i know what it is like, my sister rolled my TLC when we were going into town at about 60mph last april, we came out without a scratch because my TLC was a tank... Glad to hear your 4Runner was a tank too
I have done my own testing in 4Runners TLCs all equiped with atleast VSC and ABS. The Idea of VSC and ABS is to keep the wheels spinning the same speed as the road is passing, ABS is to prevent lock up, VSC is to prevent overspining the tires. You did everything in the situation right, but you should have had you foot still on the throttle, thats why VSC did not do anything noticable... If you would have left it on it would have instantly cut the power to what it should have been to keep the tires spinnign aproxomitly as fast as the road, which is designed for ultimate traction. But since you pulled your foot off the accelerator you did what the system was going to do but you took all power away where as the system would take what was dangerous away. this mostlikly caused the read tires to spen slower than the road thus no traction was created. Applying Brakes in this type of a slide would have possibly rolled your car, the brakes would have gripeed the front and spun the front more out as the center of weight is not and probably rolled depending on the grade. The absolute right thing you could have done was steer into it, keep your foot on the gas, and pray. two of which im sure you were doing. I know how hard it is to react in that situation, ive been in it too many times. But when an SUV nearing 5000 lbs goes Sideways on flat land it takes a skilled driver to recover, going downhill you need a few angels... Anywho glad you OK.