Almost Killed
 

Today after coming back from getting my Citizenship, I was driving at about 65 on the highway in my Honda Prelude, 53N, with quite a bit of traffic around me. Suddenly this Dodge Caravan comes up on the shoulder and cuts me off in the left lane as he merges in. I slam the brakes and try to get out of my lane. Well, I start spinning, in spite of ABS, almost hit the median, then some control, but oo wait, then more spinning. Totally I spun 900 degrees. When I was done I was facing the traffic...not a fun thing to look at. I wish morons like that guy didn't exist :mad: .

Things that came to my mind was that:

1.) Holy shit, how did I not hit anything with so much traffic around!
2.) If I had been in the 4Runner, I would have rolled 900 degrees instead of spinning.
3.) If I had been in the X5, I would'v slammed on the brakes, which might have been enough. Worst case, I would have had to make an emergency lane change, and DSC and Corner Brake Control would have saved my ass. In the end I would have thought he was a jackass and kept going.

Not being in our X5 when I needed to be, just made me appreciate it a whole lot more.

btw, what is the correct procedure when doing this kind of lane change as far as shifting gears in a manual transmission goes? Just put it in neutral?

Hey Vin,

Glad you made it out okay.

you probably don't realize it but most likely, you jacked the wheel as well.
If you just hit the brakes, your car would never spin.
Also, the prelude is a front wheel drive car.

I am going to assume, obviously this is the fault of the guy in front of you. But you made some unwise decisions in terms of car control to throw a front wheel drive car ( I am assuming it was not wet on the road and no snow ) into a spin like that. I am guessing you really slapped your tank and unsettled the car.

Going 65 (on dry road) there is NO way, MY car could have stopped in time, our X might have, but prolly not. Instinct made me slam on brakes and try to change lanes. No extreme turning of the wheel. I really don't know what happend.

Glad your OK. 53N can have some crazy drivers, but that's the first I've of something like that.

OK, it is obviously ordained that you must get rid of all other vehicles, and only drive the X5!

Vin,

Now can I convince you to take a car control course.. (I recommend this for everyone.)

So, here's what probably happened.

a little basic car control lesson: A car only does 3 things, it brakes, it accelerates and it turns.
Having said that, basic physics demands that at any given point, your vehicle has 100% of it's ability (TRACTION) to do any one of those three things.
- Meaning, you can accelerate with 100% traction, Turn with 100% traction or brake with 100% traction.
- you can also divide the traction - 90% acceleration/10%turning. 85% braking, 15% turning, etc. etc.

What you can not do is defy physics. You can not get 110% traction or ability out of your car. Once you have met the threshold of 100% anything that happens after that either decreases your performance (like locking the brakes,) or will throw you into a spin or understeer/oversteer.

- so now lets look at what happened to you. You slammed your brakes as hard as you could.. (using 100% of your traction to stop the vehicle) And then cut the wheel to change lanes (exceeding that 100% traction)

At this point, your braking and turning was toooo much input for the car and it BROKE FREE of stability.
Had you lifted off the brake a little, you could have gotten some steering input in because the car would not be using ALL it's ability to stop the car.

Now when your car was trying to stop full force, all the weight of the vehicle was forced onto the front tires, that's like 3000 lbs. Which was fine, until you cut the wheel. By cutting the wheel, the back end of the car which was relatively weight free broke traction and started to come around on you. By the time you knew what was going on, you were probably facing ass backwards.


- The point of all this info is not neccessarily for you to understand it all, rather, it is to illustrate that there is a clear, concise reason your car did that. Understanding why it did that is the key to helping you next time your in this situation. You can learn everything I just talked about in one day of driving school.

B

The old saying with a manual tranny...."When you spin, but foot in; when in doubt, both foot out" (Both foot in meaning, pressing the brakes and clutch vs. if you fishtail or plow, then let go of the accelerator, brakes, and clutch and steer yourself out of trouble). However, I agree with above, you should get some driving school course for car control....

Glad you are Ok. I have seen terrible drivers on I90/I94 in Chicago. Makes me wonder how they got their license.

While I did slam on the brakes and try to steer, wasn't ABS suppose to save me some? :dunno:

Who cares about why you spun or whether ABS should have prevented it. You're OK, and that's all that matters. Glad to hear you made through that ordeal with nothing other than maybe a bruised ego.

By the way, congratulations on your ciitizenship! :thumbup:

Juan

Vin,

The purpose of ABS or "anti-locks" is to prevent your wheels from locking..
Once they lock, you have surpassed 100% traction.

The purpose of ABS is to keep you at the threshold of 100% traction without going over it. Either way, your still AT or above 100% so any major steering inputs will put your car at the edge or over of control.

Glad you had an angel on your shoulder :thumbup: - personally, If I'm about to really get messed up because of some idiot, I'm going to make sure he is a part of what happens and not get off scotfree :mad: - that said, when the situation arises, you naturally do the best you can, which often let's the cause of everything get away. :(

WOOW B-line thanks for the lesson, i'll try to remember it next time i'm about to crash.
Seriously though, it's a very good car control lesson, mind posting anymore?

These are supposed to be good...

Linkage

He does.. cuz that's how you learn from the mistakes. If you don't know what you did wrong, chances are you will do it again...

Thanks for your input guys. While I don't want to dwell on what happend today, I think it is important to learn why it happend. So the quick lesson was much appreciated :) . Anyway, good night to all of you, and have a great FF :thumbup: !

I am having a hard time checkin out the FF thread until night these days since I am at work :( . As I am interning this semester , it kinda sucks just having a desk where anyone can drop by anytime.

Wow! Do I want to want it to be Friday so bad that I thought it was or what? Anyway, sorry if the post made no sense. Have a great Almost Friday guys.

Scarry stuff!! Glad u r ok. I had a similar experience about 15 years ago--it ain't fun, but since you are able to walk away without any physical scars, it ain't all bad! :thumbup:

Gee V, was this part of the citizenship test? Man, we are getting outta control.


Anyrate, glad u are ok

B-line - Question for you regarding this old adage, as you clearly have a lot of race experience...
I've taken a few driving classes, and have a rudimentary knowledge of the art of car control. However I don't get much "track time" to practice and hone the craft.
A few years ago, in my 328Ci (RWD, or course) I stupidly decided to power oversteer through a wet left-handed sweeping corner (NEVER a good idea on public roads!! :tsk: ). I was a bit too aggressive, and the back end swung very hard and fast... as I counter steered, I lifted off the throttle completely. The result was a bigger swing the other way, and then a BIGGER swing back again... each swing was harder to control, until I finally started to reel things back in [being very careful not to "over-correct" my counter steering inputs], somehow avoiding the curb on my right all through the corner.
So my question is, would I have been better off by backing off the gas half way or so (rather than lifting entirely)? From what I've read since that day, backing off the throttle about half way is better at regaining some semblance of grip to the rear wheels than lifting off entirely...

Also, clearly, different cars require very different techniques to drive fast... I'm somewhat new to AWD; do you have any performance driving suggestions for the AWD X5 that may not be intuitive for some one used to RWD?

Thanks,

When you lifted off the gas you got the dreaded "tank slapper". You must modulate the throttle (ease back) in that case or go to full brake. The reason you went back and forth was because you unloaded the weight of the car from rear to front by snapping off the gas, thus putting all the weight on the nose and inputting the steering. I think you figured that part out. Glad you made it o.k. Remember in rain, you can always add throttle, but it's harder to decrease speed......

Thanks for your post... but I actually didn't unload the rear by snapping off the gas and unweighting the rear... [I know that in many cars - particularly those designed to have the rear end weighted for maximum cornering grip, like the 911 - snapping off the gas in mid-corner will result in unweighting the rear wheels, reducing the size of the rear tire contact patches, and then it's spin city.]
But in my case, I (intentionally) broke the rear wheels loose with the throttle in mid turn, which is why the back end swung. So the question is, in this case, is backing off the throttle a better remedy than lifting entirely and relying on steering alone???

In addition to proper modulation of the gas, it is extremely important not to overcorrect on your steering input and/or hold the wheel in a static corrected position. 99% of people will turn the wheel too far and hold it for too long when trying to correct their direction in a skid rather than making continuous steering adjustments that match the action of the skid.

I most important tip I ever picked up in a driving course was that when the tail starts to swing out, you need to point the wheel along the path you want the car to follow (think of an imaginary cross-hair attached to the 12 o'clock position on your wheel that you want to keep pointing at where you want the car to go). Then, as the tail starts to swing back, rather than hold the wheel position (which results in overcorrection) you must smoothly and continually adjust and bring the wheel back along the path you want the car to follow.

For example, if the tail starts to slide in a corner, rather than cranking the wheel in the opposite direction and holding it until the tail starts to aggressively swing back (which will result in overcorrection), merely move the wheel just enough in the opposite direction so that you continue to steer along the path of the turn (with a slight and smooth reduction in right pedal if dictated). As the tail starts to come back, match it by moving the wheel back at the same pace and continuing to steer along the path you want the car to follow. If you do this properly and smoothly you will find the tail will come back right on line the first time with no further "tail wagging".

It's a very cool feeling when you can control a skid as smoothly as you can with this technique, but it requires patience and discipline not to do what your reflexes tell you to and yank the wheel too hard, too far, and hold it too long.

Yes, there's a good chance that, even though I was cognizant of the proper technique, I may have over-corrected. As I described - unlike instances where I've practiced the tail slide in controlled circumstances - I was driving pretty fast, and the back came around VERY hard, and quick... so I can't be sure that my corrections were just right. [I did my best :o ]
But it sounds like what I've subsequently read about modulating the throttle instead of an abrupt 'both feet out' technique is the better way to go in this situation.
{B-Line, do you care to weigh-in on this?}

Thanks for the suggestions!

Sorry for my late chime in..

- Ok, here's the first thing you need to remember. When you are driving a car, what you really are is a "weight distribution engineer" meaning all the work you do prior to a turn should "set-up" the vehicle to have weight on the right portion of the car.

B&D is correct. A "Tank Slap" is a term that comes from motorcycles when all the fuel is "SLAPPED" from one side of the tank to the other. This force of fuel and weight change can be very dangerous. We use this same term for cars even though the fuel in your car is probably not heavy enough to bring your car around. (BTW, I will readily admit, I have slapped many tanks in my day, even with experience, it happens.)
- Ok, so now lets think about what tank slapping really is: As B&D stated, you are UNSETTLING the weight on the portion of the car where you need it. And it's a lot of weight. All of sudden, you correct, and you are throwing all that weight, very fast, to the opposite side of the car. THE CAR HAS NO FOOTING. As a result, the rear does not "GRAB" it breaks "free".

It's hard to say what to do in this situation. Really depends what's coming up in front of you. The best answer I can give is, BE SMOOTH... No matter what you decide to do.. DO IT SMOOTHLY.. Nothing fast or hard or abrubt. That will only make the situation worse.

Also, never look at the wall you are about to smack in to.. BIG MISTAKE !!
Always look ***WHERE YOU WANT THE CAR TO BE***** not, Where the car is going...

If you keep your eyes where you want the car to be, react smootly, calmly, keeping your eyes on the "safe exit" your chances are much better of regaining control of the car. You are giving the vehicle a chance to "resettle the weight" while applying throttle, lifting throttle, or easing the brake. Sometimes you will find a little blip of throttle might be want you need. That will put the weight onto the rear wheels, expanding your tire patch and giving you more traction.

B

Oh yeah, AWD...

Ok, here's a trickey one. The whole point of AWD is to have your front wheels pulling you while your rear wheels are pushing you.
So, if the rear breaks free, I would want to put my foot down (accelerate, it's counter intuitive though until you get used to it.), smoothly of course. That would allow my front wheels to pull me out of the turn even though my rears are just spinning.

The thing about AWD that people need to remember, if your foot is not on the gas, it is no different than a RWD. So, in bad weather, you are much better off driving in a lower gear with power going to your front wheels. If you get in a jam, you have the front wheels pulling you out.

Once you hit the brake or lift, there is no difference.

AWD is a great feature for traction. You just have to know how to use it.
I see plenty of soccer moms driving around in SUV's in the snow that think there safe because they have AWD, in reality, they have no concept how to use it. You really need to push the car and accelerate when basic instinct is to slow.

So my answer to the AWD question is, if your rear breaks free, try to accelerate **EYES UP** **EYES AT SAFE EXIT** and smoothly accelerate towards your goal.

B

that is the gospel as moses wrote in the car control bible people... live by it. =)

Makes sense... thanks!

Regarding the RWD 328Ci, again, the 'fun' started when I (intentionally) broke the rear free by nailing the gas hard enough to invoke a wicked power oversteer (as opposed to lifting and getting the classic weight-shift loss of traction that you described... ) Don't know if this changes your advice at all for this particular situation, as lifting off the throttle once I was already swinging hard probably didn't have much of a weight transfer affect. (?)
My real question about that occurrence was if backing off the throttle would truly have been better than lifting completely... and it seems like the answer is yes for multiple reasons! ;)