Safe Speed Forums

Following on from George Painter's thread about the cornering incident which led to someone losing a foot as a result of someone taking a corner at an inappropriate speed - it struck me that this is a skill which few drivers are actually taught.

Now each corner is unique - but there are various procedures. The Mad Doc did give some clues when responding to George - but I do think we should discuss how much we understand of the art of cornering.

I am not going to give answers in this opening post - but will steer you towards a discussion by asking what exactly do you understand by the following:

1 Cornering Forces - What are they? How does a cornering force affct the feel and handling of your car? What do you feel when cornering? What does this tell you about your own skill?

2. What is meant by "positioning?"

3. What do I mean by "applying an extra edge to your observation?"

4. What is the effect of braking in a bend?

5. Describe what you understand by "braking procedure".


Just a few things to consider to kick start you all!

The procedure I tend to use is to match speed to forward vision. If the corner tightens I lift off gently and if it opens out I accelerate gently. I don't brake on bends as I know that can send you into the scenery. The weight transfer in the corner goes to the outer wheels so braking just sends it to the outer front wheel unless you have some sort of fancy brake compensation facility which will reduce this effect ( but might reduce braking force at the same time)

I think that is pretty much what my driving instructor taught me to do. When I first learned to drive I would get things wrong and go into corners a little too fast but I always kept my foot where it was or maybe lifted off gently. I usually choose a speed so that if there was an obstruction after the bend then I could do any hard braking on the straight bit after the bend rather than on the bend itself. I don't drive anywhere near the limit of grip (or at least I don't think I do) so in theory it should be possible to do some braking within a bend but I still don't think it is a good idea.

As for positioning I either reduce the severity of the bend by straigtening it out if the visibility is good enough or I adopt the big curve approach and move out to the left for a right hander and vice versa. I don't often cross the white line when straight lining but it does come in useful on some roads where it is very twisty and you can make better progress and also see further.

Changing between an awd and a rwd vehicle has made me realise more about the effects of acceleration on cornering (especially in the wet!). With awd I found the car's attitude was very neutral. It is pretty neutral under braking and acceleration and while changing gear. Having changed to a car which is rwd unless it detects rear wheel slippage and moves the drive to the front it is a total different ball game. Accelerating just a little too much with a slight curve leads to large back end out movements and the correction of the car is disconcerting as I correct before it realises things are wrong so it applies drive to the front which upsets the whole apple cart. With a car like this you are advised to keep your foot on the gas and steer into the rear ward movement and wait for the active 4wd to kick in. I have yet to be brave enough to do this! This car definitely needs some time on a skid pan to get used to as it is totally different.

It depends on the corner as to how much feedback I get. With the awd drive car I feel cornering forces more as the car rolls more in corners so I can feel the weight transfer. The tyres also make a slight noise when you start to get to a point where going faster would be a bad idea. The rwd car is totally different as there is very little body roll and bucket seats and the active torque split means you can get to sillier speeds and to some extent it keeps the car going where it thinks you want to go (providing you have the balls of course!)

No idea about your point 3 unless you mean using things like lines of trees & hedges and window reflections etc.

No problem whatsoever with braking in corners, as long as you remain within the friction circle, and are aware of the effects of weight transfer. The only condition under which braking would "send you into the scenery" is if you were already using up all available traction with cornering forces AND were committed to a line which you could not widen.

Indeed the "no braking in corners" philosophy robs us of an essential means to avoid accidents. If I encounter a hazard whilst cornering then it is useful to know that braking is one option that is open, as long as I have not foolishly put myself in the situation noted above.

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CSCP Latin for beginners...
Ticketo ergo sum : I scam therefore I am!

Oh yes, JT.

You saved me the trouble of posting that basic explanation. But there's more... Ask yourselves: "If I can't brake in a bend, then what speed is safe?" If you are not allowed to brake then the only safe speed is zero and we're stuffed.

There's more on:
http://www.safespeed.org.uk/braking.html

"Never brake in a bend" is dangerous and false advice.

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Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

Think IG is getting at the heavy brake in bend which loads up the pressure on on outside front tyre or the heavy brake on slithery surface which leads to skids. Nowt wrong with feathering brake on approach to alert car behind that you are slowing and nowt wrong with a gentle touch of the brake whilst negotiating the corner.

S bends ..... lots of those where we live .... Even more where my wife grew up You get to know when and where you can brake without unsettling the car

Have a look at the police roadcraft handbook it has an interesting and useful technique regarding following the point enclosed by the 2 sides of the road at a bend. Basically as you approach the bend if the point is moving around the bend the speed you are approaching at will allow you to safely negotiate it as the bend is opening out. If the point is not moving your speed is too high to negotiate the bend.
Read the handbook it makes a better explanation of it than me but its a good technique, it must be the police use it.

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It's Champion Man

True Chumps

I could scan the page and place it here - but there is a little more to the skill than this. You have to look into and beyond the bend and try to gain advance views beyond the exit point.... what is your exact procedure?

I would like you to visualise bends you are familiar with and talk me through your procedure on here so that I can "feel" the road with you and visualise the lay-out - each detail.

It does help tone up your skills - and we are trying to help our lurkers like the van driver ....though I would suggest he books refresher lessons and purchases "Road Craft" and really reads it

Mmmmm, I'll have to get my composers hat on and give it a good thinking at.

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It's Champion Man

Okay, I'm going to have a stab at this. Be forgiving though. Plain old driving license, no advanced doobies, and Mrs Gatsobait and her IAM brain has gone to bed and can't help me cheat.

Cornering forces sounds like (being very literal here) the forces acting on the car when cornering. Do I win a prize? No? Okay, I'll keep going then. So, if I'm going at 40 in a straight line and then enter a bend without adjusting speed the car's inertia (may not be correct term, but physics books got chucked years ago) will mean it wants to carry on in the same direction rather than take the bend. It's forced to take the bend by friction between the tyres and the road surface overcoming that, plus loads of body roll in Mrs Gatsobait's car though very little in mine (makes up for it by shaking my teeth out over level crossing s though). One tyre has to take most of the load, which I think is the front outside on the way into the bend and the rear outside on the way out. That's just an educated guess on the basis that front wheel drive cars like to understeer when driven too fast into a bend and rear wheel drives oversteer instead, which I imagine doesn't happen much on the way in (long time F1 fan, which is probably where I first heard of over/understeer). Too much body roll or any sensation that a wheel may be losing grip or spinning off and parking up a tree too fast! Or possibly even

Credit to Mrs Gatsobait for correcting me on positioning for bends. What I used to do was what probably most drivers do - start on the outside, take the shortest path round the bend by drifting towards the insdide of the bend at the apex (without crossing into the other lane on r-handers of course) and then begin to drift back out again. The missus explained that this wasn't too bright as you see round the bend better by following it round the outside as much as possible. Or is the "extra edge to observation" thing? Either way, I've found that since I've been doing that I also take bends at a more leisurely pace. Not that I was going round them suicidally fast before, and not that I'm really going much slower now. It just feels a bit more relaxed. Might be all in my head though.

Extra edge to observation could mean loads of things beside moving the car so you can see a bit more of the road beyond. Seeing movement in the gaps between trees, reflections in shop windows and parked cars, seeing the beam from headlights on the road before you can see the car they're coming from. Just being alert to anything that might give you fractionally more notice of what's coming. Suppose it might even include being able to hear something before you see it - I can usually tell when a car with aftermarket steering wheel and gearknob and a Max Power sticker on the back is coming by the sound of the shelf bender speakers they usually have. Shite! I'm turning into my dad.

Not at all sure about the last two. I have used the brakes in a bend and have lived to tell the tale, though some people do seem to think that it's a good way to have a crash. AFAICT the only effect was that it slowed the car down, though I suppose panic braking so hard you lock the wwheels might not be a lot of fun. As for braking procedure, it's always seemed like a good idea to me to get that over and done with by the time you get there. If I've been reading the road right I ought to be able to slow gently in advance, actually to have judged whether I need to slow down for it. A lot of the time I find just easing off the accelerator does enough, though if anyone is close behind me I now press the brake just to make the lights come on. I'm open to being shot down in flames on this, but I feel that if I have to worry about extra braking in the middle of a corner in order to feel safe, then I was probably going too fast in the first place.

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Make everything as simple as possible, but not simpler - Einstein

Perfect answer - read the hand book....lol.

Truthfully, Roadcraft is a very useful tool and gives very good advice - the best advice for cornering is, "Always stop in the distance you can see to be clear".

The other thing it makes very good reference on is the limit point - this directly links to the above quote as it is the point on the road that you can see to be clear. Imagine driving towards a right hand bend, the point at which the left and right curbs merge is the limit point. As you approach the bend, if you are too fast that merge point will remain stationary or move towards you, as you begin to brake to the correct speed that point will begin to move with you. If you set that point at slightly greater than your stopping distance for the speed and the point is moving with you you have the right speed. As you begin to leave the bend the limit point will begin to move away from you and as the road opens out it will sprint away from you to the next hazard.

Some other great points have been raised here such as cornering forces and tyre grip, remember that you grip is shared between three factors, Steering, braking and acceleration. If you need to do more than one of these things then you must be aware of the grip factor or you wil go into a skid.

Also remember that the most efficient and safe way to corner is to keep the car in balance - a car moving in a straight line at a steady speed is most in balance, you need to be aware of the cornering factors again here. Get the speed right, get the gear right and then apply a little gas to maintain speed and balance through the corner.

Remember this - Information (limit point) Position (line for best visiubilty through the corner), Speed (braking or accelerating) Gear and acceleration. Apply each in turn and in order and you are using what is known as the System of Car Control.

I could go on all night about this - if you'd like to have some more info let me know. But buy Roadcraft......it is very good.

Rich[/b]

My comments are more about high performance road based driving and really only apply to closed road events and in many cases would not be appropriate for normal road use but here goes.

I have done quite of bit of closed road racing in events like Targa Tasmania and Targa New Zealand (without pace notes!) and even though I am one of the best overall drivers in the competition (3rd outright, 4th outright and 10th outright) I can honestly say I have never even tried to analyse how and why I do what I do in a corner.

About the only thing I can conscientiously say I do is to look past the corner at the scenery ahead and use things like power lines and cuts though tree lines to predict where the exit point might be and then come back to the corner and follow it through, always focusing on the furtherest visual point but from there it just "happens".

As for braking mid corner I have to say that since the advent of good ABS systems my attitude has done a 100% back flip. Before ABS I would have said to brake BEFORE turning into the corner and NEVER brake in the corner unless absolutely unavoidable. Now I say, brake wherever and whenever you need to maintain the best position on the road. During these events I actually brake to the apex of the corner and accelerate once I feel that the corner is opening and if I get it wrong simply brake again. I can remember one corner that was about a 300 degree turn and I pre-empted the exit point twice and had to brake before finally having the corner open.

On normal road driving I do much of the same except that as I can only use my half of the road (on a blind corner at least) I do not start accelerating until I can actually see the exit point or feel the corner “unwinding”. As I do on a race track I also use the widest arc possible by starting from the centre line, on a left bend, cutting to the apex and finishing back at the centre line and doing the inverse on a right bend. I think this is fairly natural to most drivers anyway but I do it because the wider the arc the more speed you can carry safely.

Sorry to carry on but the topic got me thinking…

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Ross

Yes I'm a hoon, but only on the track!!!!

The basic tools of my driving are:

(1) Look as far ahead as you can to predict upcoming situations and plan in advance your actions

And that's it The rest follows on from that. Sorry Paul I don't think this is the message you think should be conveyed to most drivers though But I feel fine with that one

Andrew

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It's a scam........or possibly a scamola


Homer Simpson

Ahh, but that's NOT the fastest line on the road - nor the best in many cases.

If you do cut to the apex, most commonly you can't see as far, and since it was visibility rather than grip that limited your speed you need to slow down a bit. Obviously is the bend is "open" and there's no restriction to vision, then the line you suggest may be the fastest. But if it's really open and there's no oncoming traffic then I'd recommend using the entire width of the road.

There's also the possibility of more late adjustability and a faster exit with a late apex plan.

So these are the priorities:

First position for safety...
Then if you can do so without compromising safety, position for vision...
Then if you can do so without compromising vision or safety, position for "greatest radius" (=lowest stress, = fastest line).

I'm not quite sure how one fits the late apex strategy into this pattern.

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Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

In my experience if you cut to the true apex of any corner you CAN see the exit of the corner. If the corner is fairly tight the apex will be almost completely around the corner, not at the centre of the corner. So in that case the apex of the corner is late but it is still the apex.

The example I have given is meant for two way traffic and of course, if the road is both clear and visible, I would use the entire road. That is especially true on right bends as in most cases there is a clear view of the oncoming road and traffic on it and if clear the apex is actually on the other side of the road.

In rare cases I have used the entire road on blind left bends but only where I have had a clear view of an empty road very shortly before the bend and I know for a fact that there are no points of entry to the road between my furtherest point of reference and the corner. Driving on a steep sided mountain road where there is obviously nowhere for a road to enter would fit the bill.

Your three priorities are exactly what I do.

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Ross

Yes I'm a hoon, but only on the track!!!!

I don't think the geometrical apex is ever "late". That's the driver in you making the "best" apex the "true" apex.

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Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

In every driving course and racecraft course I have attended (dozens) the apex is determined by the exit of the corner and may also take into consideration the following corner if it is very close.

So on a hairpin the apex is about 3/4 of the way round the corner.

Normally a right angle corner will apex at approximately the centre point but if the first corner is followed closely by another corner in the opposite direction the apex may move further around the corner whereas if the first corner is followed by another corner in the same direction the apex may move back from the centre.

The true apex is the apex and it is also the best apex. All three terms describe the same point. Any other point is either NOT the apex or a false apex.

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Ross

Yes I'm a hoon, but only on the track!!!!

You missed my point I think. A mathematician with a compass would find a geometrically precise apex in the "centre" of any constant radius curve.

It's only when we take a driver's perspective that a "late apex" has any usefulness or real meaning. I agree absolutely with your driver's perspective.

Anyway, if it wasn't for the mathematician's view we wouldn't know to call it a late apex would we? Later than what? Eh?

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Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

Out of the mouths of mathematicians eh, I have never been one but I understand your comments.

On the road though an apex is based on the driver’s perspective, not those of a mathematician.

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Ross

Yes I'm a hoon, but only on the track!!!!

We're trained to look at limit points for appropriate speed for the bend, then position without compromising safety to provide the largest safe arc round the bend until the bend opens up, at which point we should arc round the apex point.

Normal driving does not demand the extremes of these positional moves, and I believe that we as trafpol in our everyday driving should emphasise positioning for safety rather than progress or the tiniest vehicle sympathy benefit.

So a nice wide arc for safety and view, but do not compromise safety for any other benefit. (Watch the rh bend lean from kamikaze bikers!!).

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Fixed ideas are like cramp, for instance in the foot, yet the best remedy is to step on them.

Ian

I'm not sure what "arc round the apex point" means. Can you clarify please?

I'm a big fan of planning a tight exit line (this would be positioned towards the left after a left hand bend), but once the road beyond the bend can be seen to be clear (assuming we're still cornering, which is usual) the best choice is to wind off the lock and wind on the power and take a nice wide fast exit, using the full width of the road if it is safe to do so.



Yep. Good point about the bikers. I've encountered about 3 of those in the last year with the helmet a good couple of feet over the centreline. The risk of the bikers moves the optimal position about three feet left at the apex point. (closer to the "racing line", and compromising vision to a small degree.)

Ian, what advice are you guys getting about "offsiding" these days? (offsiding is the practice of approaching a left hand bend on the "wrong" side of the road when conditions permit.) Offsiding is fast and enhances vision considerably, but it's bloody dangerous if it's done in the wrong place or under the wrong conditions.

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Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety