How to drive a car on a slippery road?
When the road is covered with melting ice, try to keep on the lane with a more intensive traffic. There, the ice crust melts faster, and therefore the movement is safer.
If you need a stop, look for a place on the road, free of ice and snow. If there are no such sites, it is preferable to stop on dry rolled snow.
Do not stop on the ascents. It is difficult and dangerous to move from a place on the rise in conditions of poor adhesion.
On a slippery road, try to maintain a constant speed, use the gas pedal gently, smoothly. Lower the speed before the turn and intersections beforehand. Crossroads are especially dangerous in winter for two reasons: firstly, there is a threat of collision with other cars, and secondly, the cover before the intersections is usually slippery due to the constant braking of cars.
Before lifting, select the appropriate gear and speed. The calculation should be very precise so that you do not have to add gas during the ascent.
Every year the number of drivers in our country increases by an average of 300 thousand people. Some of them had to learn to drive in winter, snow and ice, and they got the most basic riding skills in such weather. But most of the new owners of fresh driver's licenses face the glaze for the first time with the onset of cold weather. At the next lesson of our driving school (the previous one see "Science and Life" No. 12, 2001) about the features of the "winter" ride to the newly-made drivers, the candidate for master of sports in automobile racing Dmitry Zykov tells. However, it is useful and experienced drivers to master some specific "winter" techniques.
The time when motorists put their iron horses in the garage for the winter was gone irrevocably. Most drivers drive now in any season, including in winter. However, winter driving requires special attention, accuracy and certain skills. On some features of driving on a slippery road, we will stop.
It is known that in winter it is safer and easier to drive an all-wheel-drive car than a one-axle drive car, and the latter for winter are preferable to front-wheel drive vehicles. However, neither the full nor the front drive will not help if the driver is mistaken in basic situations. Note that the controls of all-wheel-drive vehicles have a lot of features and in emergency cases are significantly different from the methods of driving with a drive for only one pair of wheels.
On the winter road, many situations that could be simply ignored in the summer on a dry road are fraught with the most serious consequences.
All the further reasoning and recommendations are based on the fact that during the movement the wheels of the car should rotate (no matter how trite it may sound). The point is that in the rolling wheel the spot of contact with the road is stationary, therefore, the frictional force arising in this place is maximal (the magnitude of the friction force of rest, as is known, is maximal). It is worth the wheel to slip, as the friction force drops sharply - on the ice by several orders of magnitude compared to dry asphalt - and it can not exert any influence on the machine.
So, let's analyze a few typical situations, errors in which can lead to an accident.
On an icy or slippery road, the car does not respond to the steering wheel and continues to move straight ahead (Figure 1). Usually in such a situation there is a desire to turn the steering wheel even steeper. Do not do this! Steeply turned wheels even easier to slip on the road, and this will lead to a complete loss of control. In this case, return the steering wheel to the starting position and try again to smoothly rotate. Usually it works.
Many drivers, remembering the lessons in the driving school, try to enter the turns smoothly, gradually increasing the angle of rotation of the wheels (Fig. 2a). But it is enough to make a little mistake in the choice of the speed of the turn, and the front wheels can fall into a slip. In this situation, the error lies in the incorrectly chosen path of motion. It is more correct at the moment of entering the turn to turn the steering wheel to a larger angle (Fig. 2b), and on the arc either do not change it or reduce it. To the entrance to the turn, the front wheels do not slip into the slip, you need to "load" them with the weight of the car. It is not difficult to do this: at the last moment before turning sharply close the gas or turn on the lower gear. (Open or close the gas - press or release the accelerator pedal, respectively increase or decrease the fuel flow and increase or decrease the engine speed.) The car, as it were, "bite your nose," the springs of the front suspension will be compressed, the grip of the front wheels with the road will reach a maximum. At this point (it lasts about 0.1 sec) and you need to start turning. Immediately after the start of the turn, slightly open the gas (slightly pressing the accelerator pedal). Together, this technique is called "load - turn - pull" (Figure 3).
On a slippery road, you need to use the brakes very carefully, especially in bends. In many cases, it is better not to touch the brake pedal at all. For example, if there is already an error in the turn as described above, and the wheels are turned all the way, braking with wheel locking (as it is sometimes called - yuz) will lead to a complete loss of controllability. The machine will simply slide along the road like a village sled. If the car has got into a deep (in amplitude) drift, the braking will transfer it into a lateral slip. If the machine starts to rotate, it is better to squeeze the clutch for a short time than to press the brake. Once again, as long as the machine is moving, the wheels must rotate.
As for a terrible dream, forget about coasting on neutral gear or with the clutch off. On the driving wheels there should always be a "traction reserve". They control the "thrust" of the gas pedal, any schoolboy knows, but there are many ways of working with the accelerator pedal, and they are different for cars driven to the front, rear or all wheels. It is especially important when driving in difficult conditions to learn how to act synchronously with the steering wheel and the gas pedal.
When skidding the rear-wheel drive car on a slippery road, the steering wheel is turned towards the drift and the gas is completely closed. The driving wheels will slow the rotation, and the development of the skid will stop. On the all-wheel drive car, you need to turn the steering wheel in the direction of skidding, just cover the gas, that is, leave some traction on the wheels. The rear wheels will slow the rotation, the skid will stop developing, and the traction will remain on the front ones, and they will "pull out" the car. On the front-wheel-drive vehicle, "add gas" should be added. Two scenarios are possible here: the first - the front wheels begin to slip, the skid will stabilize (the car will go sideways), and then equalize. The second option - with the normal grip of the front wheels with the road surface with the addition of gas, they simply pull the machine to the desired trajectory. On the front-drive car, the front wheels should be pointed in the direction to move. On a slippery road the gas pedal works very smoothly, avoiding unnecessary pressing without the need.
Very useful on a slippery road can be a clutch pedal. It turns out that it can be used not only for gear changes, but also for controlling the car on a slippery road:
- if after the skid the machine starts to rotate, a short (!) release of the clutch can stop the rotation;
- when starting from the place on the ice, the clutch will help to avoid slipping the drive wheels: holding the pedal, make sure that the wheels do not slip;
- With loss of traction in snowy virgin soil (when the engine speed starts to fall strongly), a short-term release of the clutch will help to raise the speed;
- In case of emergency braking, the clutch will soften the inclusion of the lower gears.
At the last moment, we will dwell a little more.
This technique is called engine braking. When you need to reduce the speed, cover the gas, the engine speed will fall, and the car will go slower. Then make peregazovku, engage the lowered gear, for example after IV-th - III-yu, and again cover the gas.
Peregazovka - reception, which is used when switching gears from higher to lower. With its help, it is possible to eliminate the sharp deceleration of the driving wheels and their friction in sliding. The sequence of the reception is as follows: turn off the clutch, turn the shift lever to neutral, engage the clutch (simply release the pedal), briefly open the gas, then simultaneously squeeze the clutch and remove the gas, turn on the lowered gear, gently turn on the clutch. Gradually moving to the lower gear, up to the 1st, you can slow down the movement of the car almost to a complete stop, even on ice. This technique is very useful on slippery descents, for slowing down before steep turns and even just before traffic lights in a city where in winter very often there is a so-called snow roll.
As for braking itself, on slippery roads it is necessary to apply only the impulse method. Perform this technique will have to learn, but "the sheep is worth the candle." There are two methods of pulse braking: intermittent and stepped. In the case of intermittent braking, it is necessary to press the brake pedal very briefly, sharply and repeatedly (Fig. 4a). Wheels will only stop for a moment and begin to rotate more slowly than before each previous depression of the brake. As a result, the machine will stop faster than when braking "to yuz." To learn this technique is easy - choose a safe slippery pad and practice first at a small speed, increasing it gradually, as you learn to feel the moment when the wheels break into slip. This is one of the most important elements of driving skills.
When you learn to accurately determine the edge of the effort on the brake pedal, after which the wheels begin to slide, you can go on to work off the stepped braking reception. Its essence boils down to repeatedly pressing the brake pedal with a constantly increasing force (Fig. 4b). Each time, a little before making the wheels slip into slipping, you need to release the pedal slightly and instantly repeat the pressing with a little more effort. The reception is not simple, it requires a serious training, but with it you can confidently stop the car, even on the slippery surface.
On front-wheel drive vehicles, it is advisable to master the "gas-brake" method - simultaneously pressing the pedal (the brake with the left foot and the gas pedal with the right foot). This technique does not stop the engine, and most importantly - it makes it easy to turn the car on the arc with the rear (!) Wheels. If the front wheels of the car at the entrance to the turn slid and the car stopped "obeying the steering", without releasing the gas pedal, with your left foot, press the brake lightly. The rear wheels slip into the skid, the car will take the correct position in the turn, while losing some speed. After that, gently open the gas. The front wheels "stretch" the car. A few hard training will help to catch the feeling of skidding, will teach him to control. Then braking with your left foot will enable you to drive a front-drive car in a "controlled skid." In this way, you can confidently pass even very steep and dangerous turns. Mastering the reception is also not easy, but not less useful than impulsive braking. At first, you will constantly deaf the engine, but when you learn how to dose the left foot pressure on the brake pedal, everything will turn out. Practice.
In winter conditions, the parking brake lever in skilled hands turns from a passive control to an active one. This is especially important for cars with automatic gearbox and front-wheel drive cars. He can replace the braking with his left foot. Short-term braking of the rear wheels by "hand-held" will cause their drift, and the car will occupy the correct position on the trajectory of rotation. This technique also requires training. Here you need to learn to act with leverage confidently, vigorously and very quickly, accurately dosing the time of its inclusion. In long smooth turns, it's enough that the rear wheels only begin to slip into the skid, and to fit into a sharp turn, sometimes you have to make the car slip "fan", then "handbrake" must be held much more.
On a slippery road to go to higher gear, preferably with a small pause on the "neutral", to make the acceleration softer. When switching on low gears, it is recommended to use gas over. Winter conditions require the use of combined braking with the sequential inclusion of lower gears, which will prevent the occurrence of skidding. Especially important is the combined braking for front-wheel drive vehicles.
Now let's talk about tires, it largely depends on how successful this or that maneuver will be. A self-respecting driver must have two sets of tires (summer and winter), preferably with disks, so as not to create problems for the tire service when changing the season.
Increase the stability and manageability on a slippery road will help special winter tires. Hard tires with standard studs of anti-skid are suitable for out-of-town, heavily icy roads or roads with rolled snow. Spikes should be placed on four tracks, preferably at least 10-12 in the contact spot of the tire with the road. For driving in a city where roads are cleaned and the main danger is snow-and-salt porridge, softer tires with high lugs are better suited. Studded wheels should not be wide to increase pressure on the ground. And wider soft profiled tires increase the contact spot with the road. Use in winter tires wider than those recommended by the manufacturer - the car manufacturer can not. Because of the low specific pressure on the ground, they will constantly slide along the road.
Some drivers set in winter on the driving axle studded tires, and on the second axis leave the summer tires. So do not in any way should not. All four car tires must be the same model. "Raznokolesitsa" sometimes leads to paradoxical results. For example, a rear-wheel drive car has a propensity to slip the front wheels, and in the front-drive - to skidding rear.
In winter, even more than in the summer, it is dangerous to pump the wheels. The hard wheel with increased pressure has less than the stain of contact with the road, which is provided by the manufacturer, and can easily break into slip.
In winter, as in the summer, it is preferable to use tubeless tires. They are safer than tires with cameras, they are not afraid of small punctures with wires from metal brushes and even with nails, softer behaviors on the uneven surfaces, lighter tires with cameras and, consequently, have a lesser inertial effect on the suspension.
Owners of expensive and not very expensive cars equipped with antilock braking systems (ABS) have some advantage when driving on slippery roads. ABS prevents wheel locking, and this allows you to brake in a corner, often saves the car from the occurrence of skidding, gives an advantage in urban traffic with a shortage of distance.
But along with the pluses, ABS has its drawbacks. For example, if the wheels of one side hit the ice or the vehicle is thrown onto the unevenness of the ABS, keeping the stability of the car worsens its braking dynamics.
To avoid such situations, on uneven slippery roads (for example, a rolled snow-covered country road, on which a caterpillar tractor recently traveled) use impulsive braking, although this contradicts the instructions. Impulsive work with the brake pedal causes the ABS to turn on for maximum braking forces and significantly reduces the attenuation of the braking dynamics.
On our roads, more and more modern imported cars are equipped with additional control systems: automatic transmissions, ABS, hydro or electric power steering and brakes, traction control systems, cruise control, differentials of increased friction, etc. However, any driver driving such a car, should understand that one can not rely on automation only.