Driving Development Driver's Handbook: Index
Automotive engineers split safety into two types: primary (or active) and secondary (or passive). Primary safety encompasses all the features of a car that help you to drive safely and to avoid collisions, while secondary safety is the protection given to the occupants in the event of a crash.
Primary safety is affected by the following points.
How well does the vehicle hold the road on different surfaces? Sometimes cars with tenacious grip on dry roads fare badly on slippery surfaces.
Road-holding is a minor factor (driver behaviour being the major one) in crashes involving skidding into other vehicles or off the road. It is more significant for the effect it has on drivers' confidence (drivers who lack confidence are at greater risk).
The vehicle's handling has a substantial influence on the degree to which its driver feels in control, particularly in slippery conditions. Driving a car that has unbalanced and/or inconsistent handling can be stressful and may undermine a driver's confidence - thus leading to increased accident risk.
Some cars are "a real handful" for the average driver in typical emergency avoidance situations, with a tendency to spin out of control. By contrast, other cars are docile and stable, and do not require a particularly high level of skill to control even in extreme situations.
Nowadays most cars have pretty powerful brakes and differences between cars in outright stopping performance are small. What does make a major difference to safe braking is whether a car is fitted with an anti-lock braking system (often called ABS after the original Bosch version with the German name Anti-Blockier System). Such a system allows you to brake as hard as possible and yet maintain steering control (which is lost instantly when wheels lock under excessive braking with a simple, non anti-lock system). Anti-lock brakes are probably the most effective active safety device to be fitted to cars in recent years.
Acceleration can be a double-edged sword. Undoubtedly, some drivers will use a car's acceleration to excess and for its own sake; they may be more prone to aggressive behaviour in a high-powered car. On the other hand, the car's ability to accelerate has a direct bearing on the time that it is exposed to danger in overtaking manoeuvres. On balance, good acceleration is a safety feature provided the driver has well-developed skills and a mature attitude.
The kind of acceleration that counts in the real world is the ability to accelerate well from medium revs in any gear, rather than a car's "test track" performance when driven flat out to maximum revs in each gear.
A car's overall ease of control affects the driver's level of stress, confidence and fatigue. Awkward major controls such as an obstructive gearchange, or poorly placed minor switches, may distract the driver and increase the risk of accident. Drivers who do a lot of city centre driving usually find cars with automatic transmission more relaxing.
Many collisions directly result from drivers' not seeing hazards in time. While this is often related to drivers' level of awareness, anything that impedes drivers' view from their vehicles contributes to the risk.
Visibility is affected by:
Vehicles that are easy for other road users to see are less likely to be involved in collisions. Brightly coloured, clean cars show up best, particularly on dull winter days and in deep shadows. Vehicle lighting is important, including prominent direction indicators and brake lights.
Brake lights that are mounted on the car's rear roof pillars (as they are on a few new designs) or supplementary central high level brake lights have proven very effective in reducing rear end collisions. Figures from the USA, where high level brake lights have been compulsory for some years, show that the proportion of rear end collisions has been reduced by 53% since their introduction.
Drivers who are uncomfortable or experiencing backache are distracted and stressed - and more likely to be involved in collisions. Good seat comfort is an important safety factor, particularly with high-mileage business drivers.
Noise, vibration and harshness can also be distracting, fatiguing and stressful, particularly for high-mileage business drivers.
A driver's overall level of alertness, awareness and ability to concentrate is influenced by the air quality in the car. Cars with a tendency to be stuffy when the heater is operating may make drivers feel sleepy. This tendency is most common in cars that have heating and ventilation systems incapable of delivering cool air at head level while the driver's legs and torso are kept warm.
The safest cars in respect of air quality have good air conditioning systems, as these allow drivers to remain cool and calm even on hot days (collisions increase in heat waves as drivers get hot and bothered, and their tempers fray).
Whatever the specification of the car, air quality is very much under the control of the driver. Many drivers starve themselves of oxygen or overheat their brains through their own misuse of the car's heating and ventilation.
Primary safety can be assessed by inspecting and driving the car, and maintained by routine checks. Remember it's not just a car's agility in avoiding obstacles that makes it safe. All other factors being equal, a quiet, comfortable car has better primary safety than one that fatigues or distracts the driver.
Secondary safety is affected by a car's:
Secondary safety isn't something you'll want to verify through firsthand experience. We have to rely on the results of crash tests and statistical analysis. In general, larger cars offer better crash protection than smaller ones.
Consider how your present car rates in the areas affecting primary and secondary safety.
If you have a choice of car, to what extent do you consider primary and secondary safety when making your decision? Do you compare specifications of cars and examine the points listed above when taking test drives?
Regardless of how safe you consider your car to be, you still have to check certain items for safety defects on a regular basis.
Every time you drive, make sure your car's steering has none of these faults:
Always be alert for symptoms of suspension faults, such as:
Vehicle Condition: rule 28
Loads: rule 29
Seat belts: rules 40 and 41
Children in cars: rule 42
Car telephones and microphones: rule 43
Your life is literally riding on your tyres. So it's vital that you know what they're capable of, and how to keep them performing at their best.
Each tyre grips the road through a contact patch roughly the size of a man's footprint. If you apply a force to the tyre greater than its grip, it stops rolling and starts sliding. Too much power causes wheelspin, too much braking locked wheels, and too much cornering force a skid. The maximum grip in any direction is represented by the distance from the contact patch to the edge of this oval.
Forces in different directions can be combined but the resultant force must stay within the oval or the tyre will slide. The more grip being used for cornering, the less grip available for braking or accelerating, and vice versa. In the example in the diagram, if you use ninety percent of the tyre's maximum braking grip (the vertical line), the greatest cornering grip the tyre can develop (approximately half its maximum) is shown by the horizontal line. If you were to brake harder or to turn more tightly, the resultant would extend outside the oval and the car would skid.
The grip generated by any tyre depends on the friction between the road and the tyre. Every driver appreciates that stopping distances are longer and cornering speeds need to be lower on slippery surfaces. The sizes of the ovals of grip in the next diagram indicate the relative grip on different road surfaces.
All of the following tyre safety checks are vitally important.
The exact specification of a tyre is moulded onto its sidewall. If your car is brand new, the manufacturer will obviously have fitted the correct tyres. But if you take over a car from another driver make sure that all four tyres are as specified in the car's handbook.
When replacing tyres, make sure that the same make and type are fitted on all wheels. Mixing different tyres will give unpredictable handling. Unknown brands are best avoided.
Tyres perform at their optimum only when they're at the right pressure for the load they're carrying. Incorrect pressures reduce roadholding, upset handling, spoil ride comfort and increase wear.
Check your tyres' pressures, including the spare, at least once a week, and when the tyres are cold. Use your own, accurate gauge - service station gauges tend to get knocked about. Remember to refit the valve caps.
Always set pressures as recommended in your car's handbook, making the advised adjustment for heavy loads or sustained high speeds.
The sidewalls of modern tyres, particularly low profile types, are vulnerable to damage. Inspect them regularly for cuts, bulges and scuffs. Remember to check the inside walls, too. If you find any sidewall damage, replace the tyre.
Check the depth of tread at several points around the tyre and across its width. Legally the minimum tread depth is 1.6 millimetres across the central three-quarters of the width around the entire circumference, but such a shallow tread depth provides little resistance to aquaplaning. For safety's sake, replace tyres well before the tread is worn down to the legal minimum.
Look for uneven tread wear - it's a symptom of a fault.
A tyre that's worn more in the centre than at the edges has been over-inflated, while excessive wear at both edges indicates under-inflation.
Wear on one edge usually indicates that the wheel is out of alignment or, if it's on the outer edges, it could be caused by poor cornering technique.
A shallow patch of tread at one point on the circumference indicates that the wheel is out of balance.
Handling is a term used to describe a car's behaviour when cornering. This depends on the balance of grip, how it changes and how quickly it changes.
Tyres generate cornering grip by running at an angle to the car's direction of travel. This is known as the slip angle. The greater the slip angle, the greater the grip - until, at about twelve degrees, the tyre slides sideways.
The tyre's behaviour is very much like that of an aircraft wing. A wing generates lift by operating at an angle of attack; the greater the angle, the greater the lift. But when the angle is too large, the wing stalls. Pilots stall planes when they raise the nose too much when trying to increase lift. Drivers stall tyres - which then slide sideways - when they try to turn even tighter after the tyre has reached its optimum slip angle.
If a car is driven in a circle and gradually increases speed, the slip angle doesn't increase directly in proportion to the speed. At first, as speed increases the slip angle changes very little. If the steering wheel is held still, the car continues to follow the same circle. Then a critical speed is reached and the slip angle increases dramatically. The steering wheel has to be turned considerably more to stay on the circle. The car is now at its maximum cornering speed for that radius and surface. If speed is increased further, the tyre stalls and no matter how much the steering wheel is turned the car slides outwards, wide of the circle.
A car is said to understeer when the slip angle is larger at the front wheels, so the driver has to turn the steering wheel more than expected to follow the desired path.
A car oversteers when the slip angle is larger at the rear and the car feels "twitchy", turning more than expected.
When the front and back slip angles match, the car has neutral steering.
The position of the car's centre of gravity affects handling. When a car is driven along a curved path the cornering force that tries to push the car outwards effectively acts through the centre of gravity. If the centre of gravity is exactly central between the wheels, the cornering forces are equal front and rear. But if the centre of gravity is nearer the front (as it often is) the front tyres have to resist more cornering force that the rear ones.
The position of the centre of gravity also determines the proportion of the car's weight on each wheel. The greater the weight, the greater the grip between the tyre and the road. When the centre of gravity is nearer one end of the car, the extra grip of the tyres at that end helps to offset the extra cornering force they have to resist.
When a car is changing speed, the proportion of weight being carried by each wheel differs from the proportion carried when the car is standing still or moving at a constant speed. When the car accelerates the nose rises, the front wheels carry less weight and have less grip, and the rear wheels carry more weight and have more grip. When the driver brakes the nose dips, the front wheels have more grip and the rear wheels less.
When weight is removed from a wheel and the grip reduced, the slip angle increases in compensation to continue to generate enough cornering force to hold the car on the same curved path. If weight shift is very pronounced - through an abrupt change of speed - while cornering, the tyre with reduced grip can stall and suddenly slide.
In general, cars with a short wheelbase have more pronounced weight shift under acceleration and braking than those with a long wheelbase. Thus large cars tend to have more stable handling than small ones.
When engine power or braking forces are being fed through tyres that are cornering, the slip angle has to increase to maintain the same level of cornering grip. The more engine power being used or the harder the brakes applied, the bigger the slip angle.
Tyres are more likely to stall and the car to skid when hard acceleration or braking coincides with cornering.
See Tyre Grip in chapter 3.2 Tyres for an explanation of how tyres handle combinations of forces acting on them.
Chassis engineers try to ensure that handling changes are predictable and gradual. Even so, a car's handling can change suddenly when the tyres reach the limit of their grip. Many drivers find this out too late. Take advantage of any opportunity to explore your car's handling in a safe place off public roads.
While there are variations in handling between models of cars, there tend to be certain characteristics in common depending on whether the engine drives the front wheels, rear wheel or all four wheels.
Front-wheel drive cars usually understeer. With most of the mechanical components positioned at the front, the centre of gravity sits well forward. Most of the side force during cornering therefore acts on the front tyres, which have to generate more grip by running at larger slip angles than the rear tyres.
Understeer is pronounced in older designs of front-wheel drive cars, but clever chassis design and development has now reduced it to a minimum.
Front-wheel drive cars invariably understeer more if you accelerate when cornering. Weight shift reduces the grip at the front tyres while, simultaneously, the same tyres have to transmit more power to the road. Both factors cause an increase in the front wheels' slip angle.
Most rear-wheel drive cars are front-engined, with the bias of their weight towards the front, but not as much as with front-wheel drive cars (the rear location of some transmission components produces a more even weight distribution). Because of this they tend to understeer moderately at steady cornering speeds.
Cars with the engine mounted well back (like most front-engined sports cars) may have their centre of gravity exactly midway between front and rear wheels. Although this allows them to be neutral in their handling, they usually have just a little understeer designed in to aid directional stability.
When more power is applied to the rear wheels during cornering, understeer tends to increase at first - as the load on the front wheels lightens. But excessive power reduces the rear tyres' cornering grip, increases their slip angle and leads to oversteer. Unless corrected by steering in the opposite direction and reducing power, the car will spin.
Many drivers, especially inexperienced ones, find rear-wheel drive cars trickier than front-wheel drive cars on slippery roads, largely because rear-wheel drive cars are much more likely to go through a transition from understeer to oversteer in the same corner.
Cars with rear engines (like the famous Porsche 911) tend to be most tricky of all, and require a high degree of skill to drive quickly and safely (which perhaps is why many enthusiasts find them so compelling). Once a rear wheel slide has started, the heavy weight slung behind the rear wheels acts like a pendulum, and a complete spin is difficult to prevent.
Four-wheel drive used to be found only on off-road "Jeep"-type cars. Now it's often fitted to high-performance road cars. These are usually derivatives of two-wheel drive models. Handling characteristics are usually similar to the two-wheel drive versions of the same model but with better balance at the limits of grip.
Applying lots of power when cornering invariably increases the drive wheels' slip angles. In a two-wheel drive car this happens at one end only, making the car unbalanced. But in a four-wheel drive car the extra slip is minimal - because the power is distributed to all four wheels - and occurs at both ends, so the car tends to drift neatly.
Off-road four-wheel drive vehicles have handling characteristics very different from normal road cars, and require special driving techniques. Drivers unfamiliar with such vehicles are advised to obtain specialist driver training before driving them on or off the road.
If you have an opportunity to do so in a safe place off the public road, explore your own car's handling characteristics. Particularly notice any changes in balance as you approach the limit of tyre grip, and the effects of acceleration, deceleration and braking on cornering behaviour.
Every day, as you look around you on the road, you can see countless examples of drivers who don't seem to appreciate that cars are adjustable. They might be peering just over the steering wheel and struggling to see where they're going. They might be so squashed up or stretched out they're clearly unable to operate the car's controls fully and freely. Or they might be suffering unnecessary wind noise and buffeting from an open window at speed because they haven't adjusted the airflow through the ventilation system.
Unless you optimise the set-up of your car and adapt it to suit you personally, its potential to be safe, efficient and comfortable is squandered. You also need to ensure that nothing else, such as inappropriate clothing, hampers your control and comfort.
Driving is tiring and potentially hazardous if your clothing doesn't allow you freedom of movement. In modern cars it's not difficult to create an environment that's as warm and comfortable as your living room at home. So there's no need to drive in restrictive clothing such as bulky overcoats. Make sure that you can move your arms easily and fully without any tugging from the sleeves of garments.
Pay particular attention to suitable footwear for driving. Big chunky boots may be just the thing for tramping through snow or mud but they allow no feel of the pedals and may cause you to press two pedals at once. Slender, elegant stilettos may look great with that little black dress but they're just about the worst footwear for driving.
ear shoes that fit snugly, have fairly thin soles to allow reasonable feel of the pedals and flat heels for control and comfort. Women who like to wear high heels can keep a pair of flat, slip-on driving shoes in the car. It only takes a few seconds to change shoes - and you won't scuff the backs of your dress shoes on the grit under the pedals.
How you sit in relation to the car's controls has a significant effect on the efficiency and accuracy with which you operate those controls. The optimum driving position provides maximum support while allowing full and free movement of your limbs, and allows your muscles to work against load with minimum effort and absence of strain. If you find at any time when you're driving that you're tensing muscles that aren't actually being used to move controls (for example, muscles in your lower back), that's a good indication that your driving position is not ideal.
Can you improve your driving position?
Are you familiar with the full range of adjustment on your car's seat? In addition to sliding backwards and forwards, and raking the backrest, many modern car seats have variable seat cushion height and tilt, degree of lumbar support in the lower back and even the distance between side bolsters. Check whether you're making the best use of the adjustments available to you, to shape the seat for the optimum fit, particularly when you change cars or drive a different model temporarily.
Before you start making any adjustments, make sure that your pelvis is fully back in the seat so that your lower spine is against the back rest. Much back pain suffered by drivers arises from a slumped posture with insufficient support for the lower back.
Do you find yourself stretching uncomfortably, perhaps to push the clutch fully down or to reach the top of the steering wheel? Try moving a little closer to the relevant controls, either by sliding the seat forward, by adjusting the backrest to a more upright position, or both.
Are you unnecessarily cramped? For example, is it awkward to move your foot from throttle to brake and back again, or do your elbows hit the seat or door when making large turns of the steering wheel? Slide the seat backwards, recline the backrest a little or both.
Have you got the optimum view from the driving seat? In most cars, the higher you sit, the better you can see. Have you adjusted the seat height as high as comfortable without your head brushing the roof?
Can you reach all parts of the steering wheel (including the left side with your right hand and vice versa) while keeping your shoulders fully back against the seat backrest? Many drivers sit in too reclined a position for complete control. If your arms are too straight, you'll impede full and free rotation of the steering wheel.
Does your car have an adjustable steering wheel? If so, are you placing the wheel in the optimum position? As well as checking that you can turn the wheel fully and freely, make sure the wheel isn't brushing your thighs unnecessarily or obscuring part of the instrument panel. Set your seat for optimum control of the pedals, optimum view and maximum comfort, then adjust the steering wheel.
How well do your legs brace you against the car's movements? Do your feet form a broad, stable base, or do you try to drive with your knees together? (Through cultural influences - "sit like a lady" - many women drivers adopt a knees-together posture. Simply changing to a more appropriate leg position often produces an immediate improvement in the quality of car control.)
How well does the seat's backrest support you, particularly when cornering? Does your driving position allow you to get all the sideways support you need by leaning back into the seat, or do you ever find yourself holding onto the steering wheel for support?
From time to time, and when it's safe to do so (such as when you've just parked), run a comfort check. Close your eyes (to shut out the dominant visual sense) and feel the support provided by your seat. Is there an even pressure all over? Or are you aware of any particular pressure points? If so, where are they, and how can you change the shape or location of the seat to remove them?
A badly fitting seat belt won't provide you with proper protection in a crash. It may even cause injuries. And it's likely to be uncomfortable. So it's important to adjust it to give the best fit.
The position of the upper seat belt mounting point determines the angle of the diagonal part of the seat belt, and the fit of the belt across your chest and shoulder.
Many modern cars have an upper mounting point that can be slid vertically over a range of alternative positions. If the car has one, use it! Experiment to find the position that allows the belt to pass across your collar bone midway between your neck and shoulder. Too high a position can result in the belt chafing against your neck - and could cause a neck injury in a crash. If the mounting point is too low, the belt could slide off your shoulder in a crash and allow your upper body to be thrown further forward than it should, resulting in damage from contact with the steering wheel.
Whenever you drive a car other than your own, or after somebody else has driven your car, remember to adjust the upper seat belt mounting point after you have adjusted the seat and steering wheel.
Even cars with a fixed mounting usually have at least two alternative threaded holes for the bolt that holds the mounting point to the door pillar (usually concealed under the interior trim). If you find that the standard position doesn't fit you well, it's a simple matter to unbolt the upper mounting point and screw it back on in one of the other positions. Or ask your garage to do it for you.
To be effective a seat belt must fit snugly. Always check that the belt is free of twists when you fasten it, and that the lap part fits across your pelvis - not your waist (a lap belt that's too high can damage internal organs in a crash). Then pull all the slack out of the belt so that it feels snug.
Does your car have adjustable upper seat belt mountings? Do you use them? When you get into a different car, do you check whether it has adjustable mountings, and do you use them?
Do you notice how well your passengers' seat belts are fitted before you drive off? Do you advise passengers who would benefit from a better fit of the seat belt to move the mounting point?
Do you always check that your own belt is as well-fitted as possible, free of twists and slack, and capable of providing maximum protection in a crash?
Head restraints set too low to be effective are perhaps the most common examples of drivers' failing to set up their cars optimally. Some drivers seem not to appreciate that head restraints can be adjusted (apart from those on a few cars where the head restraint forms an integral part of a high-backed seat).
Head restraints have only one purpose: to protect your neck from "whiplash" injury in a crash. Whiplash injuries are caused by excessive rearward flexion of the neck, as would happen without a head restraint when your head jerks back over the top of the seat. This could happen if you were hit from behind or as a reaction after being thrown forward into the seatbelt.
If the head restraint is too low it might as well not be there. In fact, a head restraint set too low could be worse than none at all - the top of the restraint could put pressure on the upper vertebrae when a whiplash occurs.
In order to restrain your head effectively in a whiplash, the top of the restraint needs to be at least as high as the top of your ears.
Next time you get into your own car notice how high the top of the head restraint is in relation to your head. Does it provide adequate protection? If not, how long have you been driving around like that? Adjust the restraint as necessary to provide proper protection.
When you get into another car, even as a passenger, do you always set the head restraint to the optimum position? If not, is there anything preventing you from doing so in future?
Adjusting the mirrors to get the best view to the rear would appear to be too obvious to mention here. Yet many drivers fail to make optimum adjustment of their mirrors.
Do you change the setting of your mirrors in order to see what you really want to see at particular times? For example, when parking at the kerbside do you angle the nearside door mirror downwards so that you can see the back wheel? If you haven't thought of doing that, try it next time you're parking and notice how much easier it makes the task. Electric mirror adjustment is a big advantage, of course. Remember to reset the mirror to its normal position after you've completed the manoeuvre.
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As was pointed out in chapter 3.1 Vehicle safety, a driver's overall level of alertness, awareness and ability to concentrate is influenced by the climate and air quality in the car. So achieving the optimum set-up of a car's heating and ventilation system makes an important contribution to the management of road risk.
Next time you're driving take notice of the air quality and climate in your car.
Is there plenty of fresh air - or have you got the face level air vents closed? It only makes sense to close air vents when you want all the air passing through the heating and ventilation system to be blown onto the windscreen for rapid defrosting and/or demisting.
Is it warmer than it needs to be, particularly at head height? If your head is too warm, you'll soon feel drowsy.
Do you use the fan as necessary to keep a good flow of air circulating when the car is moving slowly? (Many modern cars need fan assistance to circulate air even at high speed.)
What steps do you take to minimise the intake of traffic fumes when you're stuck in a traffic jam or when following a very smoky vehicle? Do you switch off the fan temporarily, or has your car got an air recirculation switch that allows you to avoid taking in polluted air from outside?
Noise is fatiguing. It can also interfere with your ability to concentrate. While the minimum noise level in your car is largely in the hands of the engineers who designed and built it, there's no point in introducing excess noise unnecessarily. For example, opening a window to improve ventilation usually adds far more noise than switching the ventilation fan to a higher speed - and it's usually a far less effective way to circulate air, too.
Next time you're driving your car listen to it very carefully. Are there any unnecessary sources of noise?
Can you hear turbulence from a window that doesn't need to be open? Or the wind whistling round an empty roof rack that could have been removed?
Is anything rattling around in the boot or glove compartment? Can you stow it so that it won't make a noise? Does it need to be in the car now?
The more competent a driver's car control, the easier it is for that driver to execute his or her intended actions with precision. And drivers who are totally in control can feel how the car is behaving from one moment to the next. For example, they feel the car's balance (and can adjust that balance as appropriate) and can sense how much grip each wheel has. Such drivers are not taken by surprise by a car that "suddenly goes out of control."
Effective drivers invariably have a high level of car control. Yet there are highly skilled drivers who are a danger to themselves and everyone else on the road, and some quite unskilled drivers with unblemished safety records. Car control on its own doesn't make a safe driver; the other elements of effective driving must be present too. In particular, control skill must be balanced with maturity of attitude. Some highly skilled drivers show their immaturity by trying to test their skills in inappropriate environments. The race track is an appropriate place to drive continuously "on the limit"; the public road isn't.
Drivers with less than totally competent car control can manage to stay out of trouble only by driving well within their limitations and by allowing plenty of margin for error. The irony is that the effort of always making such allowances is greater than the effort of developing your control skills to a high standard.
There's a well-known saying: practice makes perfect. Unfortunately, if you regularly practice doing something ineffectively, you'll become very good at doing it like that. Sometimes you need to step back and take a detached look at what you're doing. Then you can decide to keep and refine what works well, and to rebuild skills that could be more efficient and accurate. It's also valuable to take stock of your current repertoire of control skills and to consider which new skills it would be useful to add.
The purpose of reviewing your basic skills is to help you question whether you control the car in the most efficient way or whether you just act out of habit in ways that may be inefficient. Does it matter? Yes, because inefficient technique saps energy and leads to fatigue, and it contributes to muscular tension - both of which are causes of stress.
This chapter contains a number of checks intended to raise your awareness of how you use your body to operate the car's controls in order to affect the car's behaviour, and (completing the feedback loop) how your body and senses inform you of the car's behaviour from one moment to the next. If you spot any inefficiency in your own control skills when you run the checks, try out some of the suggestions, one at a time. Changing well-established patterns of movement is bound to feel odd at first, but if you spend a little time practising the new ways they will soon feel as familiar as the old - and invariably take less effort.
The important thing is to be willing to experiment. It's not a matter of whether a particular technique is right or wrong. Whether it works as well as possible for you is all that matters. And flexibility is important too. Be prepared to vary your technique to suit changing circumstances. In all aspects of control, focus on what you want the car to do and how the car feels rather than be overly (and consciously) concerned with the technique you're using. Trust your body to operate the controls in the most natural and efficient way.
In this chapter you're invited to raise your awareness of, and to experiment with:
The ultimate test of steering control is accuracy. Does the car go exactly where you want it to go? If you can achieve the same degree of accuracy through different methods, use the technique that feels most natural, makes the most efficient use of energy and provides the smoothest changes of direction.
Steering provides perhaps the best example of how the conscious mind can get in the way of letting the body move naturally. Much of the blame lies with typical training of drivers, past and present, imposing rigid ideas of right and wrong technique.
Most people who learned to drive in Britain were taught that there is only one "correct" way to turn the steering wheel. "Pull and push" steering is a peculiarly British preoccupation that's not taught to learner drivers in other countries. Scandinavian rally drivers (who know a thing or two about good steering control) disparagingly call it "milking the cow." Unless you do it well, making large turns of the steering wheel using the pull and push method can easily result in jerky shuffling of the wheel, making the car turn in a series of sharp steps instead of in a flowing sweep.
Next time you're driving take the time to be aware of how you steer.
Notice where you're looking when you place the car accurately and, conversely, where you're looking when the car doesn't end up where you wanted it to. When you have to negotiate a narrow gap, do you look at the obstructions you want to miss or at the gap the want to "hit"? If you find yourself doing the former, see what difference it makes if you aim at the "target" of the available space.
Does the position of your hands provide maximum stability? Holding the wheel at the top is unstable, particularly on bumpy roads; the effort of holding the wheel steady is tiring. If your hands are both roughly level with the centre of the wheel, any rocking movement of your shoulders is fed directly through the centre of the wheel and is not translated into rotation of the wheel rim. So you can stay much more relaxed and steer a steadier course.
How tightly do you grip the wheel? Can you feel any tension in your arms or fingers? Tension is tiring. Experiment to find out how lightly you can hold the wheel and still have a secure grip. Vary the tightness of the grip according to need. In straight driving on a smooth road your fingers can just curl gently round the wheel rim. When you see a bumpy corner ahead take a firmer grip on the wheel just before turning - and relax your fingers again after you've straightened out.
Notice how the tightness of your grip on the wheel affects your ability to judge how much grip the front wheels have on the road. What's usually described as a car's steering feel is mostly subtle variations in resistance to steering wheel movement. How can you maximise your sensitivity to these variations?
Do you sometimes steer with one hand? This may appear to require less effort than steering with both hands (and is associated with a lazy style of driving) but in fact it requires more effort and is consequently more tiring. If you have two hands symmetrically placed on the wheel, your arms can be completely relaxed while holding the car on a steady course - because your arms are balanced weights pulling down equally on either side. With only one hand on the wheel your arm has to remain permanently tensed, holding your hand continuously at the same height. If you relax your arm, your hand drops and the car veers off to one side. You might like to focus on the tension in the muscles of your arm, and discover just how much effort it takes to steer straight with one hand.
Notice whether you move the wheel only when you actually need to change or correct your course, or whether you continually make small movements (many drivers rock the wheel back and forth without being aware of it). The latter is simply a waste of energy - the movements mostly cancel each other out - and it causes wear to steering linkages and tyres.
Pay particularly attention to the start and finish of steering movements. Are they smooth and progressive or abrupt?
When making large turns of the steering wheel, notice whether it rotates smoothly and continuously, or whether there are hesitations or pauses in the rotation. If there are pauses, when do they occur? Is it when the movement changes from one hand to the other? How can you maintain the rate of rotation through the changeover? How many separate movements do you make? What happens if you make longer continuous movements and fewer changes of grip?
How you use acceleration and deceleration has a noticeable effect on safety, fuel consumption and smoothness.
Notice how steadily you use the throttle. Unnecessary movements of the pedal waste fuel. When you need to alter your speed, notice the rate at which you change the position of the pedal. Try being more gradual in your movements and notice the effect.
When you accelerate rapidly, particularly from rest, the weight of the car shifts backwards. But how suddenly? Do your passengers' heads jerk back? Rapid acceleration needn't be jerky or uncomfortable - so long as you control the rate of weight transfer. Practise feeding in the power progressively until you can accelerate just as rapidly but make the car lean back gradually.
Do you use deceleration to give yourself plenty of time to prepare for hazards? Next time you see a hold-up ahead, notice when you lift off the throttle. If you find yourself braking to a standstill just before the traffic moves on again, try reducing the power earlier so that the car's speed falls away more gently and you can keep moving.
If you find that you often have to brake when traffic ahead slows only slightly, try easing off the throttle as soon as you see the furthest visible car begin to slow down. This creates extra space in front of you; then even if the driver ahead brakes, you often won't need to. Using the throttle in this way to adjust speed smoothly without braking is often called "acceleration sense."
There's so much more to braking than simply pressing the middle pedal. The very finest drivers are often distinguished by how little braking they do. And by the smoothness of their braking. The very best racing drivers have always produced noticeably less brake wear than their contemporaries. So skilful braking is very much a case of "less is more."
Do you find yourself braking frequently or sharply? If so, it's probably your forward planning that needs attention rather than your braking technique.
Do you try to minimise the imbalance of the car by braking smoothly and, as far as possible, in a straight line?
Notice whether you brake just once before any hazard or whether you take a second or third stab at the brake pedal. Intermittent braking makes the car pitch unnecessarily which upsets its balance of grip, so try to do all your braking in one go.
Notice whether the bulk of your braking on the approach to a hazard is done with a constant pressure or whether you brake harder towards the end of the approach? Many drivers misjudge how much braking pressure they need to slow down in the distance they've allowed. Consequently they brake too lightly at first, then realise they're running out of room and have to brake harder. If you find this happening to you, practise braking a little harder than seems appropriate initially until you can brake consistently with a constant pressure.
How does it feel when the car stops? Any jerk? It's possible to stop very rapidly without any jerkiness - by applying and releasing brake pedal pressure progressively. By "feathering" the pressure right off just before you stop, all the extra weight that was shifted forwards under braking is gradually removed from the front springs and the car rolls smoothly to a standstill. If you feel your stops could be smoother, aim to finish braking a little short of your stopping position and roll up to it.
Often drivers who are capable of feathering the brakes in order to make jerk-free stops fail to use the same technique when finishing braking on the move, after adjusting speed to approach a hazard. Notice how smoothly you taper off the brakes before corners and other hazards. Does the nose of the car rise gently or does it bounce up abruptly as the front suspension "unloads"? Notice whether passengers' heads move backwards as you release the brake pedal. If your release of the brakes seems a little abrupt, are you allowing enough room on the approach to ease off the brakes gradually or are you holding the brakes on firmly until you're almost at the hazard?
Using the gears of any car, even an automatic, requires thought and a measure of skill. How efficiently do you use the gearbox?
Do you ever labour the engine in too high a gear instead of changing down readily? Changing gear with a modern gearbox is not exactly arduous, so is there any reason to avoid it?
Do you use the gears to slow down or to "assist" the brakes? This is an old-fashioned technique that may suit a vintage car with primitive, inefficient and unreliable brakes but modern cars respond best to the adage: brakes to slow, gears to go. Slowing the car with the gearbox causes excessive transmission wear. Brake pads are much cheaper to replace than gearboxes.
Do you change down through the gears one at a time instead of skipping directly to the one you need after you've slowed down? If you do take the gears in sequence, have you ever thought about what you achieve by doing so? You don't actually need a lower gear until after you've slowed down and want the engine to drive the car again. The logical method is to slow down to your new speed, leaving the gear lever alone, and then to change directly to the appropriate gear for that speed. Any unnecessary gear changing is a waste of effort and potentially distracting.
When crawling slowly, do you slip the clutch in second gear rather than change into first gear? This is a common habit that causes excessive clutch wear. In many cases people do it simply because they learned to drive years ago in a car in which they found it difficult to select (the non-synchromesh) first gear on the move. The habit has stuck while gearboxes have improved - first gear is now as easy to use as all the others.
How much force do you use to move the gear-lever? Experiment to see how little force is needed. Then experiment with the speed and rhythm of your gear changes and see if you can reduce the force even further.
If your upward changes are a bit jerky, you're probably letting the engine revs fall too much during the change. Listen or watch the tachometer: Does the engine speed fall right off and then jerk back up as the clutch engages? Try to control the drop in engine speed so that it matches the new gear exactly by making quicker gear-changes or by keeping very slight pressure on the throttle as you change up.
When you change down do you use the throttle to lift the engine revs to match the new gear or are the revs dragged up when the clutch engages? Changing down with no pressure on the throttle is jerky unless you use lots of clutch slip (which wears the clutch). With the engine revs matched you can engage the clutch smartly with no slip and no jerk either. If you find that you only change down off the throttle while braking, either brake first and then change down when your right foot is back on the throttle, or make heel-and-toe gear changes, operating brake and throttle simultaneously (as racing drivers do). If you're unfamiliar with the heel-and-toe technique but would like to try it, it's advisable to get an expert driver to demonstrate the technique, and to practise somewhere safe off the public road until you're proficient.
Here's an exercise that will show you how well you're changing gear. While driving at a steady 30mph (25mph in a small-engined car) select every gear between first and fifth. Take them in sequence, up and down the 'box, and then at random (so you might change from first to fourth, say, or from fifth to second). The idea is to adjust the engine speed at each gear change so that the car's speed remains constant.
When driving an automatic, do you just stick the selector into "drive" and leave it there regardless of the road conditions? Or do you make appropriate use of low gear hold positions and such devices as an overdrive ratio lockout button and/or variable change programmes (e.g. economy / sport / winter)? Do you know what they're for and how to use them?
Focus on how your car feels when it's cornering. By tuning into all the available sensations you'll improve the poise and balance of your cornering - and maximise the car's grip on the road. Aim to treat the whole cornering process as one harmonious flow.
For coverage of strategies for dealing with bends see chapter 4.6 Bends.
Do you always adjust your speed for the corner in good time, release the brakes gently and change gear smoothly (taking care to match the engine revs to the new gear) - or are your actions on the approach sometimes rushed?
How do you turn the car into the corner? Is it done gradually, easing the car into the corner, or does the car change course abruptly? Notice the rate of change of the forces on your body. Do you and your passengers feel a sideways lurch, or does the lateral force just build up and die away smoothly?
How do you use the engine's power while cornering? Do you enter the turn with no power, on a closed throttle, or with just enough power to maintain a constant speed? Which method provides the best steering response and balance for your car? (The traditional approach is to apply "a balanced throttle" before turning but many modern cars respond best if you turn in on "a trailing throttle.") Notice where you are in the corner when you start to apply power in order to accelerate out of the corner. How progressively do you feed the power in? Do you link the application of power to the straightening of the steering wheel?
How do you hold your head as you drive through the corner? What effect does it have on your sensations of cornering, your sense of working with the car and the smoothness and accuracy of the whole cornering process if you tilt your head slightly in the direction of the turn?
How does the whole cornering process look, sound and feel? Does your car glide freely through the turn with no tyre squeal and minimal body roll, even when travelling quickly? Does the steering remain light in feel throughout, suggesting that the car is going where it wants to go? Or does the steering load up and the car feel like it's being forced to do something unnatural? If it's the latter, how could you be working with the car instead of against it?
Misjudgement or lack of precise control when performing manoeuvres, particularly parking, is responsible for millions of pounds worth of damage to vehicles and property every year. In many company fleets, low speed manoeuvring shunts and damage sustained by vehicles while they're parked account for the majority of repair costs.
So where do drivers go wrong? Or, to put it the other way round, what do they need to do to ensure that all manoeuvres are carried out with maximum safety and precision?
Effective manoeuvring can be broken down into:
Through lack of planning drivers often carry out manoeuvres they'd be better off not performing at all, or they fail to perform the best manoeuvre for the circumstances. It's worth reflecting on how much planning you do before manoeuvres. For example, before you start parking the car or performing a manoeuvre such as a U-turn, reversing into a side road or making a multi-point turn, do you take note of the road, traffic and weather conditions, and pedestrian activity? Do you check road signs and markings in the area? Do you always ask yourself:
Might anyone be endangered by your manoeuvre? For example, would parking here make it difficult for drivers to see whether it's safe to emerge from that junction? Would stopping here, even temporarily before reversing, force other vehicles to adopt a dangerous position to get past - for example, by crossing over the centre of the road just before a blind hill crest or sharp corner?
Is there a danger of your car being damaged if you park it here? Will it be protruding into the traffic flow? Will large vehicles be turning here, and thus likely to clip your car with their back wheels? Is your car likely to be hit by doors opening on adjacent cars?
Parking on footpaths can endanger pedestrians, particularly those with wheelchairs or prams, by forcing them into the road to get past. If you do park on a pedestrian right of way, you've only got yourself to blame if a passing pushchair scrapes the side of the car.
There are plenty of places where it's illegal to park. Just because other drivers have parked there it doesn't make prosecution any less likely for you. And flashing hazard warning lights don't make your car any less parked!
Similarly, is it legal to manoeuvre? Is there a "no U-turns" road sign? Any stopping, even for a moment while you select reverse gear, is illegal on a clearway or a road with double white lines.
Is your intended manoeuvre the most convenient that you can perform? For example, it's not worth reversing into a side road to turn round if it's only a short trip round the block. And doing a three-point turn in the road is a lot more bother, especially if there's traffic about, than swinging round in a pub car park or a garage forecourt.
Before you park, consider the convenience of others. Will you block a driveway or any other entrance to premises? Are you going to obstruct a wheelchair ramp or the entrance to a cycle path? On narrow roads with cars already parked will you leave enough space for emergency vehicles to get through? Will you make it difficult for people to get into a car alongside? Consider the needs of elderly and disabled people - has the car alongside got a disabled badge on the windscreen?
Will it be convenient for you to park here? Will you be able to open the doors easily? Will you be able to get your bulky shopping into the boot? Are you (or your passengers) going to step into a puddle when you get out?
Have you planned the whole manoeuvre? The easiest way into a parking place may leave you with an awkward exit. In general, it's preferable to park so that you can drive away directly, without having to shunt back and forth, particularly if the engine will be cold when you leave.
Getting the big picture means being aware of much more than your immediate surroundings while manoeuvring. It's very easy to become so preoccupied with trying to control the car accurately that you fail to see a dangerous situation arising nearby. For example, when reversing into a parking space at the roadside or in a car park you might be so concerned with looking into the space that you fail to notice that you're swinging the front of your car into the path of a passing car.
Damage arising from drivers' failure to get the big picture (such as the example above) is likely to be more serious than damage caused by inaccurate control (such as scraping a gate post). Continuous all-round observation is vital throughout every manoeuvre.
If you're blocking the way while manoeuvring, visualise the paths that other drivers will have to follow in order to avoid you. By getting the big picture you can stop in the least obstructive position if you have to wait for someone to pass.
If you find manoeuvres like reversing into parking bays difficult, try getting a bigger picture by visualising how the manoeuvre looks from a bird's-eye view. The idea is to hold an impression in your mind's eye of the position of all four corners of the car relative to the parking space, rather than focusing exclusively on just one corner at a time. The process of visualising the manoeuvre from a different perspective encourages complete all-round observation - you have to collect enough visual information to construct the imaginary picture.
Most experienced drivers carry out manoeuvres too quickly to be 100% safe. Ask yourself whether you always give yourself enough time for all-round observation and accurate control. The only way you can do that is by keeping your speed down.
Some drivers - particularly men - seem to think that performing a manoeuvre quickly is some sort of demonstration of their driving prowess to the world at large. It's actually nothing more than a demonstration of immaturity and a lack of concern for other road users.
Make sure you always take any gradient into account before starting a manoeuvre, otherwise you might find the car moving faster than you intended under the pull of gravity. This is easily overlooked when reverse parking at the side of a road with a pronounced camber: as you steer towards the kerb the car will roll into the gutter.
When a blind person uses a white stick to feel his way, where does his sensory awareness end? Is it where the stick touches his hand or is it at the far end of the stick? He is, of course, constructing in his brain a representation of the world around him from the tactile sensations he receives. For all practical purposes, his awareness ends at the far end of the stick; his hand grasping the stick forms the interface between two different media carrying the messages to his brain.
In a similar way, drivers who feel confident and who are competent when manoeuvring their cars in confined spaces extend their awareness to the car's extremities. It is as though they are wearing the car like a suit of clothes. As in the old cliché, they are at one with the car. Conversely, drivers who lack confidence and competence, and who never feel sure of where the edges of the car really are, have awareness that ends at their fingers and toes. They are detached from the car, separate. If you fall into the latter category, notice the difference when you imagine that your awareness extends to all corners of the car.
Obviously, it helps if you can see the corners of the car. Particularly if you aren't the world's most confident parker, and you have some choice of the car you drive, make sure that you try out some manoeuvres when you take a test drive. Choose a car that gives you a reasonable view of the corners. In many modern saloon cars the rear of the car is invisible. The view to the rear is often much better in estate car versions of the same model.
How you sit has a big effect on what you see. Is your seat high enough for accurate manoeuvring? Be prepared to twist right round in the seat when reversing; it's not enough to look in the mirrors.
Awareness of the car's extremities extends to the wheels. Take care to protect them when manoeuvring. Avoid hitting or running over kerbs when parking. You could cut or weaken the sidewalls of tyres, cause expensive damage to wheels (especially alloy ones) and knock steering out of alignment. Sometimes drivers mount kerbs when trying to drive forwards into small roadside parking spaces instead of reversing in.
Are you using all the aids available to you when you manoeuvre the car in confined spaces?
Door mirrors, for example - do you tilt the nearside mirror down so that you can see the rear wheel and the kerb when reverse parking?
When squeezing into a tight parking space in a shopping street can you see your car and the parked cars either end of it reflected in a shop window? By using a reflection you may be able to reverse your car in confidence to within a couple of inches of the car behind.
Similarly, on a sunny day you may be able to use shadows on the road to help you to judge how close you are to an adjacent vehicle.
And when you want to reverse round a corner into a side street, do you look for some sort of marker that's level with the start of the turn? Something that you'll be able to see when the kerb disappears from view below the window. A tree or a lamppost, perhaps?
Many drivers deliberately avoid certain manoeuvres. They avoid them because they lack confidence in their ability to perform them. For example, a driver might prefer to spend ages driving around looking for a large parking space rather than reverse into any of the available small ones.
Well, guess what - you won't improve your performance at anything you avoid doing! One of the simplest ways to improve manoeuvring skill is to practise.
Even if you think you're pretty good at manoeuvring, it's worth setting up some exercises to find out just how good you are. You might be surprised. It's particularly useful to practise in this way when you change cars, so that you can readjust your perception of the car's extremities.
For example, do you really know how wide the car is? In a quiet car park or similar space, place a couple of plastic cones at what you judge to be just far enough apart to drive between them. Alternatively, plant a pair of canes into firm ground. Don't look at the car as you do so; use the image in your mind of the car's width to judge the distance. Then drive between them and stop. Check how closely you've judged the width. Surprised? Adjust the gap until you've got just a couple of inches clearance on either side. Reverse well back and take a good look at the gap. Readjust your mental image of the car's width to match this reference. Now drive through the gap slowly without touching the cones or canes. Continue to practise, steadily increasing the speed, until you can drive through the gap cleanly and consistently at 20mph. Then, leaving the gap the same, try reversing through. Again practice until you can do it cleanly and consistently.
Also see how close you can get the front or rear of the car to a cone or a cane without quite touching it. Practising this until you can stop consistently within a couple of inches will give you much more confidence when parking close to a wall or in a tight space between other cars.
If your particular bęte noire is reverse parking, you could make a couple of "cars" out of cones (preferable alongside a low kerb) in order to practise parking between them. Free of the fear of denting and scraping painted metal, you can concentrate on the accuracy of the manoeuvre. When you're completely sure that you can park accurately and consistently without touching a cone or the kerb, go and do it for real.
Another useful exercise is to place a row of cones about one and a half car-lengths apart and to weave through the gaps slalom-style. Do it forwards and then in reverse. Repeat until you can do it smoothly and steadily without touching any cones.
Are there any manoeuvres that you avoid? What sort of safe practice exercises can you devise that will allow you to develop your skill and gain confidence?
Reversing: rules 129 and 130
WAITING AND PARKING: rules 137-46
You shouldn't need emergency control skills in normal driving. So why bother to develop them? Because they could save your life.
Even the best driver can lose concentration for a moment or fail to anticipate another driver's hazardous behaviour. Then a situation may quickly develop in which a collision seems inevitable - unless you have the skills to control your car at the limit of its roadholding so you can drive out of danger.
The only safe way to develop these skills is under controlled conditions away from the public road - preferably with expert coaching. Do not practise these techniques on the public road.
Emergency braking involves extracting every last ounce of tyre grip so that you stop in the shortest possible distance while following the safest course.
The most effective technique depends on the type of braking system fitted, the situation and the road surface.
Let's dispense with a common fallacy: an anti-lock braking system doesn't allow you to stop in a shorter distance than a simple (non-electronic) system - it may even produce slightly longer stopping distances. Its purpose is to allow continuous steering control to be maintained no matter how hard you press the brake pedal. By doing this it allows you to stop safely without using any special control skills.
To get optimum performance from anti-lock brakes in an emergency you may have to change some long-held beliefs about braking - beliefs like braking progressively, leaving the clutch alone until you've nearly stopped and never turning while braking hard.
Unlike an anti-lock braking system, the simple braking system found in older cars and in some manufacturers' basic models does require special emergency control techniques, especially in situations that require a combination of braking and steering.
What do you do if you've misjudged a bend, entered it too fast so the car is pretty well on its limit of roadholding and then you see that it becomes much tighter half way round? What if you've entered a bend too fast to be able to stop within the distance you can see to be clear and then you see an obstruction? You won't be able to stop before you reach it and you'll get round it only by making a tight manoeuvre.
Driving folklore says you don't brake hard on bends, and in normal circumstances you wouldn't. But in an emergency when the only alternative is to crash you can brake hard - provided you use the right technique.
How do you deal with a sudden obstacle across your path (perhaps a car that emerged from a side road just in front of you)? There isn't room to stop... but there may be a gap on one side just big enough to swerve through. You want maximum braking grip and maximum cornering grip. The knack is to keep them separate.
Cars don't skid. Drivers do - by driving beyond their tyres' limit of adhesion. Skids can occur on any kind of road surface, including dry roads. In fact, dry road skids are the most dangerous: they are often unexpected and they tend to happen at high speeds - with consequentially heavy impacts when you hit something.
Most drivers think they know how to deal with skidding. Perhaps their driving instructors explained what to do in theory and books on driving usually give advice on skid control. They continue to think that until they experience their first skid. Then they discover that skid control is very much a "seat of the pants" thing - like riding a bicycle. It's not something that you can learn from being told or reading about it. That's why there are no "how to control a skid" instructions here. They can induce a false sense of security and they're not a substitute for doing it!
Special training sites and equipment allow you to experience, in complete safety, keeping the car under control on the very limit of adhesion on slippery surfaces, and correcting skids when they occur. Given the right training environment and the opportunity to experiment most drivers learn fairly quickly to recognise and respond appropriately to all kinds of skids. Such experience is an essential part of your development as a complete, competent and safe driver.
In fact, skid control is a contradiction in terms. Skidding is a large and sudden degree of tyre slip that the driver has failed to anticipate. Until the driver regains control and the car stops skidding, the car is OUT OF CONTROL!
Correcting any skid always uses up space. The car ends up in places you didn't intend to be. Unlike a training facility, the public road usually provides very little space in which to recover from a skid. Very rarely do you have more than a car's width between you and the edge of the road, an adjacent lane or oncoming traffic. Therefore, the usual outcome from a skid is either a crash or a lucky escape.
The only true control of skids is in avoiding them. This is the greatest value of skid training - learning to recognise the indicators that tell you that you will skid if you push any harder. Drivers soon learn that there are two ways to drive quickly round a slippery circuit: in a series of alternating skids and corrections or neatly, keeping the car near the limit of adhesion but never exceeding it. Keeping it neat is invariably faster.
Have you ever skidded on the road?
What was the outcome?
How prepared were you to deal with the situation? Had you had appropriate training or practice previously? If you had, was the real thing like the practice or was it different? How was it different? Did it all happen much faster?
If you escaped damage or injury, do you consider that you did so through your skill? Or was it luck - that nobody was coming the other way, or that there was a wide grass verge instead of a stone wall at the road's edge, perhaps?
Did your driving change after the experience? Have you maintained the change?
Have you done anything to ensure that you are better able to avoid and deal with skids in the future? If not, why not?
Whether or not you have actually experienced a skid, does the possibility of skidding bother you? In what sort of conditions? How does this affect your state of mind when driving? Do you find it fatiguing?