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Astraist
Master Driver



Joined: Mar 27, 2010
Posts: 209

PostPosted: Thu Apr 22, 2010 5:01 pm Reply with quote Back to top

In my last two threads I disscussed important elements of driving a vehicle: A seating position, mirror adjustment, steering habits, and emergency braking.

Now, I will focus on several emergencies that might occur. You might be surprised to find out that, in some of the cases, the fear for such a scenario to occur or of what the driver should or should not do, is far more rare than you think, and that some of these cases are not even serious emergencies.

I will categorily state that the brakes take a considerable role in the correction of all of these scenarios. This has the additional advantage of being easy to apply in various emergencies, rather than spend a lot of time about what to do or not to do.

I will disscuss the following scenarios:

1. An emergency stop
2. Emergency avoidance braking
3. Emergency braking in a bend
4. Front-tire skid -- Understeer
5. Rear-tire skid -- Oversteer
6. A slippery surface ahead
7. Avoiding a head-on colission
8. Off-road Recovery and split-grip braking
9. A stuck gas Pedal
10.A faulty brake pedal

1.An emergency stop
A car, bike, child, crate, deer fall in front of you, what to do and what not to do?

Lift your foot swiftly off of the accelerator and kick the brake pedal down to the floor.

Common mistake: People brake far too softly. They are afraid of the response of the car from braking in all sorts of speeds, traffic and road conditions, and try to see if they can get out of the situation without nailing the brake pedal to the floor at once.

For cars without ABS: Yes, it would be best if you do not brake as hard as possible and try to keep the wheel just short of locking (Threshold braking).

The problem is that this technique is impossible to perform well in an emergency. After all, you can perform threshold braking in a car with ABS also, and stop faster than the ABS, than how come everyone tells you that you should stomp on the pedal with ABS? That's because trying to perform threshold braking, in any car, is certain to fail and increase the braking distance in comparison to locked-wheels or ABS.
Emergency braking techniques compared by Re'em Samuel, CEO of "Maslulim"

2. Emergency avoidance braking
Unless there is no room for braking, always prefer to brake first, wipe off speed and than turn aside. Even if it seems like you will not manage to stop in time, brake in a straight line to wipe off speed and than steer at a later stage (preferably right, in countries where you drive on the right side of the road).

Without ABS, you simply need to release the pedal partially or almost fully when you steer. The way to perform this whole ordeal, is to forcibly shake your whole head sideways and focus on the visual target in the direction to which you want to steer. Once you set your eyes there instead of looking on the obstacle and praying to stop, your hands will get you there. This is a very hard drill and has to be covered in a defensive driving course, unless this theory means virtually nothing.

Common mistakes: Trying to steer first, braking and than immediatly steering (without wiping off speed and without letting go without ABS), locking your eyes on the target.

Dr. William Van Tassel showing how to perform an emergency avoidance drill without braking if you really do not have room.

3. Emergency Braking in a bend
Yes, you can also brake when you are mid-corner. This is usually slightly harder, because you need to keep the car balanced to avoid any hazardous slide. However, it is not too hard to perform.
1. With ABS: Full-force braking. Do not make changes to the steering wheel at the beginning of the braking procedure.
2. Without ABS: Brake semi-hard (70%) while taking off some of the steering input.

Mistakes: Braking hard, but not hard enough, only makes matters worst, as it do not slows down the car as much as you want, but only sacrifices stability and causes the car to skid.

4. Front-tire Skid: Understeer
This is one of those not real emergencies. It is the normal occurance of a car that ploughs into a corner too fast. Instead of spinning (which is what most people think the car will do), it would simply run wide and "refuse" to turn as tight as you want it to, skidding head on and away from the corner. You can detect this situation as it's about to occur by the wheel becoming lighter.

What to do? Quickly but not ubruptly lift off of the gas, and possibly feather the brake pedal slightly. If you went in really fast and your car just runs straight in complete disobedience to the wheel, perform an emergency stop to bring the car to a quick halt.

What not to do? Turn the wheel sharply into the corner in panic. Try and be more smooth and cool minded, and correct it with your feet.

Itay Alon demonstrates handling understeer

5. Rear tire skid: Oversteer
When the rear tires are the ones skidding, the tail of the car is sliding and attempts to overtake the front and spin the car. Initially, it seems like the car is turning "too much" into the corner, hence the name, oversteer.

What to do? Brake hard and possibly try and straighten the steering, to stop the car quickly, or even stop the slide before you stop the car.

Common mistakes: Reacting to oversteer involves four kinds of people: Those who resort to the above solution (minority), those who brake, but don't hard enough, which actually makes matters worst (majority), those who keep their eyes in the right direction and automatically try to steer out of it, however risking being snapped far more violently the other way, and those professionals that know how to identify different types of oversteer and correct them with the throttle/steering/clutch accordingly.

Most road drivers are much better off braking hard than trying to control the car with either steering, throttle, clutch or a combination of them, and possibly increasing the power acting on the car and making things much worst. Here's why.

6. A slippery surface up ahead
You look up ahead and you see something colorful on the tarmac, a stain of oil, a stain of diesel, mud even, what do you do?

First, do not panic. These things are not all that slippery and if you drive straight through them you will be fine! So what we are trying to do is to wipe off speed. If there is a car behind we can move onto a different lane or possibly the side of the road and perform our emergency stop there.

If and when we need to drive through the slippery surface, we quickly but smoothly ease off of the brakes just before the stain, letting the car wipe off as much speed as possible, but giving it time to return to it's natural balance. We than keep our foot just covering the accelerator and with the wheel straight.

Brake -- ease off -- if unavoidable, keep a constant speed and straight wheel on the stain.

7. Avoiding a head-on colission
The scene: A two-lane roadway with three cars: Two driving each in it's own lane and a third can passing one of the two cars and being faced with the other en route to a head-on collission. Let's assume this occurs at a country where people drive on the right side of the road, as an example.

Solution: Brake hard and than veer to the right. If you are in the car passing the other car and you suddenly see a car coming up ahead, brake hard to allow the car you are passing to catch up with you and than steer back into your lane.

If you are in the car coming from across, and a passing car comes in front of you, you brake hard and wait for a very late stage to sharply veer to the right. Shake your head forcibly sideways and focus on the edge of the roadway or the yellow line in it's proximity, there should be enough room for all three cars to drive side by side (there's actually place for four cars, not considering the shoulder of the road).

Additionally, prefer going off-road and crashing into a tree, pole or rolling into a ditch, over hitting the oncoming car or veering towards the center of the road, unless this is a narrow mountain road or a road where there is no room to veer right. Usually, veering towards the center of the road might lead to hitting the oncoming car as it makes a last-second save, or hitting the car it's passing or a car following behind.

Both these videos are foreign, but the intentions are clear:
- http://www.youtube.com/watch?v=vGi1MiBLHLs&feature=related
- http://www.youtube.com/watch?v=DbbvAFKDELg

8. Off-road Recovery and split-grip braking

This is a situation that might be result of trying to avoid an obstacle or a head-on collision, or possibly something simply caused by being sleepy when driving on a rural two-lane roadway. One side of the car drops unto a gravel, grassy or muddy shoulder of the road.

A very common response is to suddenly panic and sharply veer back onto the road. Now, because one side of the car is on tarmac and one side on another surace, with less grip (this is called a condition of split-grip_ and usually lower in height, it can cause a spin or swerve across the road to hit something in the opposite shoulder of the road or an oncoming car.

Well, this too is not really an emergency always. You can drive the car along the shoulder-line while gently scrubbing off speed with the brakes (nothing too strong, just light or even moderate braking) and than eventually turn the wheel just slightly and let the car get back on the road by itself.

One case where this is an emergency, is when the shoulder of the road ahead is blocked by an obstruction: A pole, a try, a person. In this case, you perform an emergency stop while the car is driving along the shoulder in a condition of split-grip.

Yes, it is possible. Let me tell you a secret: Even without ABS the car normally stays nicely stable and relatively pitched forward.

http://www.youtube.com/watch?v=KFiPs8dQB4E

9. Stuck Gas Pedal
Again, this is a paranoia that completly unjustifies the term "emergency", unless it suddenly occurs during an overtake or in heavy traffic or ridiculous speeds. This malfunction occurs in other cars besides Toyotas (it happened in Loxus car with a similar electronic throttle body) and can also appear in old cars due to clamped gas cables or gas pedals.

The appropriate means of action: Shift into neutral (in a Manual car, simply press down on the clutch) and congradulations, you have just dissconnected the engine from the wheels, hence the car stopped accelerating.

Additionally, all modern cars have a injection disconnector, which will keep the revs from causing damage to the engine and transmission, although you might hear it screaming.

Once you have done that, you simply scrubb off speed and safely stop on the side of the road, and when the car is rolling to a final stop, shut down the engine. You do not want the gas on when the car is not moving.

Now, let's assume it does not work, what to do? Hard for the brakes! The footbrake is always the strongest means of car control avaiable to the driver. Braking hard (even not fully down) will be able to stop a car with the throttle fully open, and quite quickly, even if it is a Formula-1 car with 850 horsepower and Rear-wheel drive. It would surely stop a normal Toyota with half-open throttle, even if it's slightly downhill/All-wheel-Drive car/slightly worn-out brakes/from a high speed or whatever. Additionally, in many cars, the brakes will dissconnect the throttle automatically and also dissconnect the cruise control that might cause the problem. Additionally, the weight transfer during sudden hard braking (the way your body wants to leap forward) might knock the floor mat/gas cable/gas pedal that cause the obstruction.

Two comments on that: Most our cars are driven by Petrolum, in which case the brake booster will not work when the throttle is jammed and the brake pedal would feel somewhat stiffer. However, it only means your leg needs to apply more force unto the pedal, the final result in the force of the brakes remains similar!

Also, with the brakes neglected and connected to different electronic controls, some cars might be hard to bring to a full stop this way. However, you wil manage to wipe off a lot of speed to a crawling speed, at which stage you can also try the handbrake, or might consider shutting off the engine.

Even if you do shut off the engine when the car is still running, you should be able to steer and stop the car. Yes, like when the throttle is jammed, the booster will not work, but this only makes it harder to pres on the pedal, the brakes themselves still work just fine! Same with the steering, you lose power steering, but with modern racks, roads and given that the car is moving, the wheel should be difficult to manouver.

Also, about the fear of the steering wheel locking: Many cars do not even have that feature. Additionally, even if they do, the steering wheel is not that easy to lock, particularly when moving and besides, the wheel does not lock when the engine is shut off, it is locked when the ignition key is pulled out of the switch.

http://www.youtube.com/watch?v=KFiPs8dQB4E
http://www.youtube.com/watch?v=FT07_JbnKWQ&feature=related

10.A faulty brake pedal

Again, a situation less dangerous than it might sound like, and very very rare with modern cars, if you keep your tires and brakes checked every now and than.

What happens is that we press down on the footbrake and it seem to do not work. Well, first, even if the hydraulic brake system seem to not work, it never fails completly. You always have some juice, often quite a lot, left. So the first thing you do is ease off of the pedal and than reapply slightly harder. If this does not seem to work, pump the brakes several times rapidly to built up a bit of pressure and than squeeze down on the pedal to excert the most out of whatever pressure you have.

Now, we assist the footbrake with our two other brakes: The engine-braking and the mechanical brakes. Engine braking takes the most simple form of letting go of the gas pedal, and this effect can be multiplied by downshifting the gears and in bigger cars by special instruments (Exhaust brake, jack-brake, retarder). You are basically downshifting the gears in rough sequense to wipe off speed.

Eventually, once you reach a relatively low speed with th footbrake and the engine brake, you operate the mechanical brake which is the handbrake. You press the button on the handbrake in before you pull on it. Than, you gently pull it up slightly, and than pull it even more as nessecary.

If these procedures are not possible because your throttle is jammed simultanously or because your engine was turned-off or because your handbrake is also out of order, you can still manage to wipe off a nice amount of speed while manouvering the car, and possibly managing to cruise the car to stop, or bring it to a halt by running it into a soft surface like dirt or even rubbing it against the gaurdrail.

A good tip-off is to open up all windows, allowing incoming air to help wipe off speed and allow for you to audibly warn other road users and possibly call for help.

11. Sudden engine shut-down
If you engine shuts off, you simply apply the footbrake somewhat to start wiping off speed. Put on your emergency lights (they work even with the engine disengaged) and try to steer the car gently to a halt on the side of the road.

12. A front-wheel blow-out
Scrubb off speed gently and gently steer the car to safety. If this results in the car sliding in any way, brake hard to stop the slide.

13. Aquaplaning
You are driving on a wet highway or over a puddle. You suddenly feel the wheel becoming very light and the engine revs seems to climb up somewhat while the car itself copes sort of a "resistance" and appears to slow down slightly. You, my friends, are now aquaplaning.

One of the more stupied things for one to do in this case is panic. Again, this is not an emergency, and when delt with correctly will disspear quite quickly. What you do is ease off of the gas without lifting-off of it completly. If this does not seem to help, declutch or shift into neutral and only than release the pedal.

If this causes the car to skid in any way, brake hard to stop the slide
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stephenfernandez
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Joined: Apr 23, 2010
Posts: 1

PostPosted: Fri Apr 23, 2010 7:08 am Reply with quote Back to top

thanx for sharing such a great information[/url]
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