Stability and Skill in Driving (research paper)

[Jungles]

This is a quite a recent study (2002) conducted by Griffith University, Australia, regarding the effects of posture and stability in sensory perception, vehicle control, and safe driving. If you can wade through the more technical aspects of the study, some of the discussion may be useful to driving instructors who frequent this board.

http://www.fmh.utl.pt/aca/stability&skill.pdf

Abstract:

Two experiments addressed the relation between postural stability, perceptual sensitivity, and stability of driving performance. A vehicle was fitted with differential GPS for measuring position and speed, position sensors for measuring brake and accelerator depression, force transducers for measuring door, console and footrest bracing forces, and an accelerometer for measuring the 3D accelerations of the vehicle. In Experiment 1, we investigated whether the initiation of deceleration and the control of braking might be due to sensitivity to the perceptual variable tau, which specifies time-to-contact (TTC), and in particular, whether its first derivative, tau-dot, is used to maintain a constant deceleration profile. Using both untrained experienced drivers (EDs) and trained driving instructors from the Holden Performance Driving Centre (HPDC), results confirmed that, regardless of skill level, tau-dot was maintained at a value close to 0.5 and, as predicted by Lee [Perception 5 (1976) 437], braking was initiated when TTC approximately 5 s. In Experiment 2, we wished to quantify the purported differences in driving behaviour between EDs and HPDC instructors during a variety of everyday manoeuvres. Results indicated that instructors utilised a different cornering trajectory, a different emergency braking strategy, and were able to perform a high-speed swerve and recovery task more effectively than the EDs. In general, the instructors applied greater bracing forces using the door and console compared with EDs. The instructors also applied greater footrest forces during emergency braking than did the EDs. The greater use of bracing by instructor drivers to resist g-forces represents a strategy of active stabilisation that enhances both postural stability, as well as overall stability and consistency of driving performance. Results are discussed with regard to the dynamics of perceptual-motor coordination, and how increased stability might improve sensitivity to relevant perceptual information. We conclude that driver-training programmes that focus on increasing driver stability (as a pre-requisite for increased control) show great promise as a means to improving one's attention during driving, and hence have the potential to dramatically improve road safety in general. Copyright 2002 Elsevier Science B.V.

[JamesAllport]

Interesting.

I've certainly found that, having got the basics out of the way, the biggest improvements in my driving have come from changing the way I sit.

I had a day out a couple of weeks ago with a police driving instructor and HPC honourary member. He reminded me that I needed to "sit in the seat not on the seat" with my shoulders supported and use my forearms and wrists to steer instead of having classic IAM-style "helium elbows".

It meant using fixed input steering and even ( ) choosing to use rotational steering when I could have done pull-push (I know, I know ) more than I would have done without his coaching. But it worked a treat.

It made an amazing and immediate difference to the sensitivity of my inputs and the accuracy of my car control. The instructor's explanation was that because I was "more centred" in my own posture, I was better able to sense and deal with what the car was doing.

James

[wenlocksimon]

This is sheer coincidence.

I have recently started trying 9/3 hand positioning as opposed to 10/2, and have found that I need to position the seat a couple of clicks back to facilitate this comfortably for "The Hendon Shuffle".

Now, this new driving position has started a "helium elbow" (I love that one - it is soooo descriptive) effect which I find uncomfortable. So my question is this...........

Where should your arms and hands be positioned for a perfect steering action assuming you are still attempting "system" steering?????

Comments / advice welcomed.

Wen

[James]

Although I have been taught that "quarter to three" is the maximum reach around the wheel that is permissable, the "ten to two" position is the one that all police drivers are sworn to use, and are advised to stick to.

[James]

Of the hundreds of police drivers that exist, I can only go on the select few that I have encountered. "Hendon", as so many seem to recognise, certainly love the 10 to 2 position. Some at "Hendon" however may prefer the 10 to 3. It is still acceptable. It is all down to the preferentials of the individual. I prefer 9 to 3 but stick to what the job want to see.

[crr003]

I was out with an experienced police driver recently who converted me from 10/2 to 9/3 & I find it a lot more sensitive & also better when fixed input steering is appropriate. I now use it all the time.

9-3 also puts your fingers in a better position to use indicators/wipers.

[7db]

The French have a wonderful expression:- "buggering a fly", for when things get a little too pedantic at levels of detail which are not relevant...

I'm afraid I feel that hand positions whilst steering are one of those for me.

If you can smoothly apply the right amount of steering, then does it really matter which appendage grips the wheel in which fashion?


But whilst the fly is getting it where the sun don't shine...a nice light grip allows the tyres to talk back to you through your fingers -- some of the grips I have seen are the equivalent of sticking your fingers in your ears whilst in conversation with the car.

[TripleS]

The French have a wonderful expression:- "buggering a fly", for when things get a little too pedantic at levels of detail which are not relevant...

I'm afraid I feel that hand positions whilst steering are one of those for me.

If you can smoothly apply the right amount of steering, then does it really matter which appendage grips the wheel in which fashion?

No it doesn't, IMHO.

My steering techniques are many and varied, so there's always one available that will give a reliable result.

Just as a matter of interest are there any figures to indicate accidents caused by faulty techniques in handling steering wheels?

Best wishes all,
Dave.

[Jungles]

Steering grip is a very personal thing, IMHO. The best position is usually the one where the individual feels he/she has the best control, without feeling unnatural. Most of the time, this means the hands are at 10-2 or 9-3.

In terms of arm positioning, when load is placed on each arm/hand, there is a natural tendency for the arms to drift closer together as they are raised, and to spread apart as they are lowered. This is easily observable behaviour if you watch martial artists or sports fighters, where the positioning of the arms emphasise structural strength and versatility.

When the arms are at torso or shoulder height, such as when placed on a steering wheel, it matters very little in terms of stability, if the hands are placed at 10-2 or 9-3 positions. The driving environment, types of steering technique most likely to be used, and physiological characteristics of the individual matter more than general broad-brush rules.