In order to ensure traffic safety, the driver must take the following measures when driving.
Pulling off the car
Before driving, the driver is obliged to make sure that the road ahead is clear, and that there are no vehicles to the side and behind that he can interfere with the movement. Before you move off, you should turn on the turn signal. At the beginning of the movement, it is necessary to drive a certain distance straight, next to the sidewalk or the roadside, and then smoothly, without interfering with other vehicles, enter the lane and turn off the turn signal.
Movement speed and distance. The permissible speed for given road conditions depends on a number of factors, which include:
- road visibility and about visibility;
- the width of the carriageway and the condition of the pavement;
- traffic intensity of vehicles and pedestrians on a given section of the road;
- arrangement of the road with traffic lights, road signs, markings;
- distance from a moving vehicle to vehicles ahead, etc.
In cities and towns, the speed should not exceed 60 km/h. Outside cities and towns, the speed should not exceed 70 km/h.
Depending on the speed of the vehicle, the driver must choose a distance that guarantees the impossibility of a collision in the event of braking of the vehicle in front.
Overtaking requires skillful calculation from the driver and strict adherence to the rules for performing this maneuver. Overtaking is allowed on the left side of the vehicle in front, provided there is good visibility of the road. WITH right side it is allowed to overtake a vehicle, the driver of which has given a left turn signal and started to perform it.
Before overtaking, the driver must turn on the direction indicator and warn the person being overtaken. vehicle sound signal(outside the settlement), and at night by switching the headlights.
The driver must imagine whether, if necessary, he will be able to pass with oncoming vehicles that accidentally find themselves in the overtaking zone. The speed of the overtaking vehicle must not exceed the speed limits allowed by traffic rules or road conditions. Before rebuilding in your lane at the end of overtaking, you must turn on the right turn signal and take a place in your lane in such a way that the overtaken car does not slow down and does not change its direction of movement. It is not allowed to overtake at intersections (except for regulated ones), at the end of the rise and on sections of roads with limited visibility with access to the oncoming traffic lane, at railway crossings, as well as vehicles that overtake or bypass.
Braking
Distinguish between service and emergency braking of the car. The process of emergency braking of the car is divided into three phases:
1) path, passable by car during the driver's reaction time (without braking);
2) the path traveled by the car during the operation of the brake actuator;
3) full braking of the car.
Thus, the stopping distance during emergency braking is the distance that the car travels from the moment the driver detects a danger to its complete stop.
The part of the stopping distance from the moment the driver applies an effort to the brake pedal to the stop of the car is called the stopping distance. The main influence on the magnitude of the braking distance is exerted by the speed of the car. In addition, the braking distance is affected by the condition of the road surface, the magnitude of the slope of the road, the condition of the tires of the car, etc.
The condition of the road surface is evaluated by the friction coefficient, which characterizes the friction force between the tire and the road. The value of the adhesion coefficient depends on the quality of the road surface, as well as on other factors (humidity, icing, etc.). The friction force between the tire and the road on wet asphalt is reduced by half, and on icy - about 10 times compared to the friction force on a dry surface.
The degree of wear of the tread pattern of tires, the difference in air pressure in the tires of one axle, the uneven load on the tires also have a significant impact on the friction force between the tire and the road. One of the reasons for the deterioration in the braking efficiency of a car is a decrease in braking torque due to heating of the friction linings and brake drums with frequent use of the brakes or their incorrect adjustment.
Wheel lock (skid) during braking, especially when driving on wet and icy roads, leads to tire wear, an increase in braking distance, and loss of control.
In order to ensure traffic safety when working on the line, the driver must take into account the above factors that affect the braking distance of the car.
Service braking of the car in the event of a deliberate stop or speed reduction should be carried out in several steps with a smooth pressure on the brake pedal. This reduces brake heat and reduces the chance of wheel lockup. On slippery sections of the road, the service braking of a vehicle with a manual transmission must be carried out using the engine without disengaging the clutch.
Driving in reverse requires increased attention and caution from the driver. Before starting the movement, the driver must make sure that the way behind is clear and the road conditions allow the car to be reversed without hindrance. In conditions limited visibility, as well as when filing back, you should use the help of accompanying persons or other persons.
When driving on inclines and tight curves, the driver must drive at a speed that will stop immediately if necessary and give way to vehicles moving uphill. On long slopes, driving with a disengaged gear or clutch is not allowed, and on mountain roads, also towing on a flexible hitch.
Driving in difficult weather conditions
Driving in difficult weather conditions(rain, snowfall, fog) becomes much more difficult due to the limited visibility of the road situation from the driver’s workplace and a decrease in the friction force between the wheels and the road. To ensure driving safety in inclement weather, the driver should take the following measures when driving.
When driving in rainy weather, evaluate the slipperiness of the road and select a safe speed accordingly. To do this, after making sure that there are no cars coming behind, at low speed, make a sharp braking and, by slowing down the car, evaluate the slipperiness of the road surface.
To ensure visibility through windshield cabins in drizzling rain, periodically turn on the windshield wipers, after wetting the glass with water from the washer. In the event of heavy rain or snowfall, when the wipers do not have time to clean the front glass of the cab, drive at low speed to the nearest rest area, exit onto a side road or side widening and wait out the bad weather.
When it rains and in a snowstorm, do not stop at the edge of the steep slopes of the road or in the lowlands.
Dry the brakes after driving through deep puddles. To do this, moving in 1st gear, make several braking until the resistance to movement begins to increase.
When driving in fog, in the event of a sharp decrease in the visibility of the road situation, as well as a loss of orientation, move off the road and wait until the fog clears. In case of emergency, you should continue driving at a speed that ensures an immediate stop.
As a guide when driving in fog, use the center line of the road or the lines of longitudinal markings. When driving in rain, fog, snowfall, the driver must turn on the external lighting - parking lights and low beam headlights.
Driving at night
Features of visual perception of a person in the dark. In the dark, with poor lighting, the main functions of the eye are violated: visual acuity, color and depth vision; visibility deteriorates due to impaired contrast perception. During the transition from bright illumination to darkness, a person does not see anything at first, and only after a while begins to distinguish objects in the dark. The reverse phenomenon, i.e., the adaptation of the eye to light after being in darkness, is also associated with a temporary loss of visual perception. The greatest danger to the driver is temporary glare from the headlights of an oncoming vehicle. A blinded driver may not have time to slow down when passing, which leads to an emergency.
Use of external lights
With the onset of dusk, in conditions of insufficient visibility during the day, when driving in tunnels, the driver must turn on the parking lights. In cities and towns on illuminated sections of roads, the use of dipped headlights is allowed, and on unlit roads also high beam headlights provided there is no oncoming traffic of vehicles.
When using high beam headlights, the driver is obliged to switch the high beam to low beam at least 150 m from oncoming vehicles. Switching the high beam to the low beam is also mandatory in cases where it can dazzle other road users in the same direction.
In case of blinding, the driver must slow down and stop in the lane in which he is moving.
With continuous oncoming traffic at night, in order to reduce the glare of the headlights, without changing the position of the head, slightly turn your eyes to the right and navigate when moving to the side of the road.
At stops or parking lots in the absence of road lighting at night or during the day in conditions of insufficient visibility, the driver must turn on the position or parking lights. In the event of a malfunction of these lights, the driver is obliged to install an emergency stop sign (triangle) or a red flashing light behind the vehicle at a distance of 25-30 m.
Climbing
Steep climbs must be overcome in a reduction gear transfer box. It is necessary to determine in advance the steepness of the rise and engage the gear in the gearbox that provides the necessary pulling force on wheels so as not to change gears on the rise. Decrease the air pressure in the tyres, depending on the condition of the ground. It is desirable to overcome the rises in a straight line, since overcoming obliquely, with a roll, causes the unloaded wheels to slip and the car to turn. Turning is allowed only on gentle slopes. If it is impossible to overcome the slope on your own, you should use a winch.
Under good road conditions, short hills can be overcome from acceleration in the second gear of the transfer case and in the higher gears of the gearbox.
Overcoming descents
When moving to a long descent (more than 50 m long), the driver must evaluate its steepness and include those gears of the gearbox and transfer case on which he would overcome the climb of such steepness; at the same time, it is strictly forbidden to turn off the engine, as this can lead to the exhaustion of the air supply of the brake drive and turn off the power steering, which reduces the safety of the car. When negotiating such a descent, you must always use engine braking. Descent with the brakes with the gearbox or transfer case disengaged or with the clutch disengaged is not permitted.
If the speed increases on the descent crankshaft, it is necessary to periodically slow down the car, reducing its speed.
Overcoming ditches, roadside ditches and ditches
These obstacles must be overcome whenever possible when driving with low speed. In this case, the dimensions of the car should be taken into account. It is necessary to overcome ditches, especially on wet ground, at a right angle, otherwise the car may slip, roll along the ditch or ditch, and then the one-sided redistribution of the load on the wheels will cause the unloaded wheels to slip, which will lead to the need to use a tug or winch.
Driving on dirty country roads and profiled roads on clay and black earth soils
When driving on clay and black earth soils after heavy rain, the vehicle may have side slips, so the driver must be very careful when choosing the direction. When driving, it is necessary to choose relatively horizontal sections of the track, it is necessary to skillfully use the already laid track, which prevents the car from lateral skidding.
Particular difficulties for the driver may arise on excessively wet roads with a steep profile and deep roadside ditches. On such roads, move carefully along the ridge at low speed.
When operating the car during the thaw period, instead of a plug with a cotter pin screwed into the clutch housing, it is necessary to wrap the sealed plug from the spare parts kit.
Tire pressure reduction
When overcoming difficult sections of the road with soft soil, you can reduce the air pressure in the tires depending on the nature of the soil. It should not be abused by reducing the pressure by setting it much lower than it is necessary for traffic conditions. It should also be remembered that the run at reduced pressure is limited, so it is necessary to reduce the pressure only in cases of emergency.
It is forbidden to reduce the pressure when driving on paved roads to increase the smoothness of the ride.
When leaving a difficult area on a paved road, it is necessary to stop the car and increase the air pressure in diagonal tires up to 0.15 MPa (1.5 kgf / cm 2), in radial tires - up to 0.2 MPa (2 kgf / cm 2 ). A further increase in pressure to normal is allowed to be carried out on the move at a speed of not more than 40 km / h.
If the run from reduced pressure exceeds the specified value, the overall tire life will be reduced.
When driving with a load of 5000 kg, it is forbidden to reduce tire pressure.
If the vehicle is driven at high speed for a long time, the temperature of the air in the tires rises, which causes an increase in pressure; while the pressure in the tires can not be reduced.
While driving, the tire valves on the wheels must be kept open, regardless of the condition of the road. This allows you to constantly monitor the tire pressure on the pressure gauge, as well as timely detect damage to the system and tire punctures.
With a working tire pressure regulation system, it is allowed to continue driving after a tire puncture under conditions of constant maintenance of normal pressure in the tires. As soon as possible, replace the wheel with a punctured tire with a spare or repair the tube.
Overcoming wetlands, sandy areas and virgin snow
Wetlands should be passed in the first gear of the transfer case at a speed of no more than 15 km / h, reducing the preliminary air pressure in the tires.
It is necessary to move along a swampy meadow without stopping, avoiding wheel slip; start the movement smoothly, without jerks. If the wheels begin to slip, you must immediately disengage the clutch and, by engaging the gear reversing, drive back. You need to move in a straight line, without making sharp turns. If necessary, turn smoothly, along a large radius curve. Such a turn almost does not increase the resistance to the movement of the car, which eliminates the possibility of breaking the turf and slipping the wheels, which are inevitable on sharp turns. Avoid driving on the trail laid in front of the car in front.
sandy areas must also be overcome with reduced air pressure in the tires, depending on the density of the sand and driving conditions. In particularly difficult areas, slippage should not be allowed. If slipping has begun, it is necessary to drive back to accelerate and gain more speed. When moving in a column, you must follow the trail of the vehicle in front.
Snow up to 500 mm deep is well overcome by the car without reducing the air pressure in the tires. Turns on virgin snow should be carried out in the same way as when driving on a swampy meadow. With a significant thickness of the snow cover that impedes the movement of the car, the pressure should be reduced depending on the density of the snow. When driving in deep loose snow, the same traffic rules should be observed as when driving on sand.
A.A. Klyasova, Yu.I. Magaras - Sinop LLC, Moscow, Russia
A.V. Dobrinsky - OJSC Moscow Roads, Moscow, Russia
Building an intellectual transport system imposes certain obligations related to the use of high technologies to improve the quality of services at all stages of the creation and operation of road transport infrastructure. The construction and operation of roads, tunnels, bridges in many regions of Russia needs the most modern systems meteorological support, since weather conditions, especially in areas with an unstable climate, directly affect the condition of the road surface, which means convenience and, most importantly, safety traffic. Road administrations today are concerned about the rational and, at the same time, efficient spending of funds and anti-icing reagents used in the winter maintenance of roads.
Thus, weather forecasting last years has become a real reserve for reducing the negative consequences of the impact of adverse weather conditions on the road transport infrastructure. The advent of new technologies and technical means make it possible to integrate meteorological information into the operational activities of motor transport companies and the process of making managerial decisions with a significant economic effect.
Today, the meteorological system must provide not only accurate current weather data, but also the most correct weather forecast, adapted to a specific area and including not only general meteorological parameters, but also specialized data for the automotive industry, such as temperature and road surface conditions, including on bridges. , overpasses, in tunnels, etc. The next generation of meteorological systems goes even further - here we can already talk about predicting the likelihood of a risk situation caused by hazardous weather events and assessing the possible damage to ground infrastructure.
In Europe and North America, weather forecasting systems have been used to manage transport infrastructure for more than 20 years. So in Germany, in the early 90s of the last century, a centralized implementation of an information system for warning about the state of roads and predicted weather conditions, based on the forecasts of the national meteorological service and on the readings of road sensors, began. Similar or similar meteorological systems are now used in the USA, Canada, Finland, Austria, and some other European countries.
In Russia today there are a number of highways are also equipped with road meteorological stations and sensors for the condition and temperature of the road surface, while the further development of the use of these systems directly depends on the development of data processing systems and decision support systems.
Only a systematic approach makes it possible to turn the quantity of installed meteorological equipment into the quality of management and decision-making by road management bodies and operating organizations.
The most famous international project for building ITS, including a weather forecasting system, is the intelligent transport corridor Helsinki - St. Petersburg - Moscow, which was launched by the governments of Russia and Finland. The automated meteorological support system to be created within the framework of the project will allow receiving current data from installed road meteorological stations, processing them in the situation center and informing road users about the actual weather conditions in various ways, including alerts on mobile devices, radio messages and data output to roadside information boards.
This approach largely solves the problem of the availability of up-to-date weather data for all road users, but the lack of accurate predictive information about weather and road conditions in any section of the transport corridor greatly complicates the decision-making process for drivers when choosing the optimal traffic schedule. Detailed detailed and localized forecast information is also essential for road services to implement operational and planned activities. Thus, the first steps to create an intelligent transport infrastructure are already being implemented, but this is only the beginning of the journey.
To better meet the needs of road users and road services in specialized hydrometeorological information (SHMI), it seems promising to create a specialized website with real-time publication of information about the actual meteorological situation, weather forecasts and other types of SHMI in a form adapted for a non-specialist in the field of meteorology. A similar specialized site / portal that generates and integrates various types of SHMI with the ability to localize data for a custom list of objects or a specific part of the road infrastructure based on an interactive software interface is given in this work.
To create a product that meets modern requirements for the quality of weather forecasts and is easy to use by non-specialists in the field of meteorology, it is necessary to solve several fundamentally important problems. Figure 1 shows the main problems in hydrometeorological support, typical for weather-dependent sectors of the economy.
Fig.1 Existing problems in the meteorological support of economic activity and ways to solve them
The first two are associated with insufficient detail of both measured and predicted parameters. By the necessary detail, we mean a fairly specific set of indicators with the appropriate temporal and spatial resolution. Such indicators include, in particular, the density of the observing meteorological network, the frequency of measurements, the measured parameters, the availability of specialized sensors, the information of which is necessary in a particular area of economic and economic activity. The spatial and temporal resolution of prognostic information, the frequency of its update, the list of predicted parameters also have a significant impact on assessing the development of the situation and making a balanced and informed decision. To serve the automotive industry, a sufficient number of automatic road weather stations have been installed, measuring, in addition to standard set weather parameters as well as the temperature and the condition of the road surface. However, the practical use of data from road weather stations is at an extremely low level; if information about the current meteorological and road situation is used, it is rather due to the experience and intuition of the road transport industry workers.
Forecast information, as a rule, has a short lead time (4-6 hours), which allows, as a rule, to quickly respond to an unfavorable situation, but such lead time is insufficient for large-scale preventive measures that will minimize the effects of bad weather, as well as make planning realistic repair and maintenance work in the most favorable weather conditions for this.
The issue of rational and efficient use of meteorological information includes our proposals formulated in paragraphs 3 and 4 of the above figure. It is necessary to move from weather forecasting to forecasting weather risks, namely, to predicting certain consequences of the influence of adverse and dangerous hydrometeorological conditions on specific infrastructure facilities and reporting this information to the decision maker in a form that is convenient and understandable to a non-specialist meteorologist.
The vast majority of private meteorological providers, both in Russia and abroad, when preparing a forecast, use the results of those model calculations that are open to access. Different providers in different countries also prefer different models, which they find either more accurate for a certain region or more convenient to use the results. However, any model calculations need to be "calibrated", i.e. in eliminating systematic error. This process must be constant and continuous and is based on the use of information about the actual weather, i.e. on weather station data. Accordingly, only the largest and most well-equipped providers, both technically and intellectually, can “calibrate” one model of their choice and only for settlements, from where they receive data on changes in the actual weather. This explains the possible diversity of forecasts for the same locality from different providers: based on the results different models and different methods of eliminating systematic error were applied. It is fundamentally important to develop such a forecasting algorithm that would not rely on a single model, but would allow combining and combining the available forecasts of various forecasting systems. Essential additional and necessary conditions are the analysis of the spatial structure of prognostic and actual meteorological data and the generalization of algorithms for constructing "synthesized" forecasts for points of an arbitrary computational grid, in which there are no observational data. A similar problem is solved in the prognostic technology used in the system proposed below. Almost none of the providers provides the consumer with a service that takes into account the possible negative consequences of the complex joint influence of forecasted weather conditions directly on the activity of the industry with an assessment of the likelihood of such consequences. The decision maker does not have a tool for assessing possible risks caused by hydrometeorological events. Similar situation does not allow efficient necessary measures aimed at the preliminary mobilization of forces and means to minimize possible losses and ensure normal operation the entire infrastructure. In our work, we also proposed a solution to this problem.
SINOP system today is a fundamentally new solution for Russia, which allows you to automatically make forecasts of the meteorological situation and weather risks in real time. The system consists of four main blocks, including weather forecasting, information and analytical tools, hydrometeorological risk forecasting and risk management.
Weather forecasting block. To monitor current weather conditions, data from almost all existing meteorological stations in Russia and Europe, as well as data from the customer's own automatic weather stations, are used. With the participation of the Hydrometeorological Center of the Russian Federation, a unique technology, which has no analogues in Russia, has been created for the automatic generation of a multi-model synthesized forecast of the main meteorological characteristics with a high degree detailing for an arbitrary geographic area. The system provides hourly weather forecast for 72 hours with hourly automatic updates. Today in Russia it is the most accurate local meteorological forecast, which is also used in forecasting special parameters- in the road industry, as a rule, this is the temperature and condition of the road surface, the coefficient of adhesion (slipperiness).
All data is displayed on a geographical (transport) map, where zones are allocated heightened danger depending on the actual state of the weather or forecast conditions: sleet, ice, sticking wet snow or the formation of ice-frost deposits on the wires of the contact network of urban transport and power lines, prolonged or intense precipitation, abnormally low or high temperatures and others (Fig. 2 and 3).
Fig. 2.3 Displaying the forecast of meteorological elements and areas of increased danger on a geographical map. All information in one window.
Information-analytical block. This block is responsible for the identification and formalization of weather risks for a certain industry infrastructure and the subsequent formation of a weather risk matrix that reflects possible consequences(Fig.4). Based on data on the causes, nature and parameters of newly occurred events caused by adverse meteorological conditions, the risk and damage matrix is adjusted.
Fig.4 Example of a simplified weather risk matrix
The flat matrix given above is rather conditional. In fact, such a matrix is multidimensional, since usually takes into account not one, but several qualitative factors that affect the derived event, and each of these factors may also have a quantitative characteristic or range of values. Moreover, with a well-formalized description of specific infrastructure facilities, a quantitative forecast of damage, expressed in financial terms, is also possible. As an example of a multidimensional approach to the formation of the concept of "event forecast", we will cite such a well-known phenomenon for motorists as "black ice". "Black ice" is a type of winter slipperiness that occurs on a dry road surface in the form of an ice film due to the sublimation of water vapor from the air at a road surface temperature below 0 ° C and below the dew point temperature. This definition is given from ODM 218.8.001-2009 "Methodological recommendations for specialized hydrometeorological support of the road sector". Even from this short definition, it can be concluded that black ice forms under certain combinations of air temperature and humidity, pavement temperature, and in the absence of precipitation. These conditions are necessary but not always sufficient. Local features, previous weather, time of day, cloudiness, etc. may be affected. In the first approximation, the conditions for the formation of black ice can be written as follows, which is shown in Fig.5.
Fig.5 A simplified example of the formation of the conditions for the occurrence of black ice according to the given meteorological parameters.
A map showing areas where black ice formation is predicted, automatically built based on the forecast of meteorological parameters and specified conditions, is shown in Fig.6.
Fig.6 Territory subject to black ice formation according to weather forecast and risk matrix.
Forecasting weather risks. To solve this problem, within the framework of the SINOP system, a technology has been created for automatically generating a specialized forecast of the place and time of occurrence and further development risky situation. The forecast is made in real time based on the interaction of weather forecasting and analytics blocks. Based on the forecast of the hydrometeorological situation and the weather risk matrix in automatic mode possible consequences of the impact of adverse weather conditions on infrastructure facilities are predicted. A flexible interface allows you to set specialized criteria for adverse conditions, forms of presentation of meteorological data, definition of algorithms for notification of occurred and predicted events. At the same time, the user can independently determine and adjust the criteria for the level of danger for each of the significant meteorological parameters or the complex effect of the total impact of several of them on the infrastructure.
Fig.7 different colors the areas of automatically predicted various dangerous weather-dependent events are shown.
The system automatically sends messages about predicted and occurring dangerous or unfavorable hydrometeorological phenomena for the transport infrastructure, as well as about the predicted consequences in real time, including to mobile devices.
Additional integration of the SINOP system with GIS and BI systems allows expanding analytical capabilities, including for assessing the probability of occurrence and extent of damage.
Management of risks. In addition to forecasting weather risks, the system provides information necessary for operational planning. The system implements the functionality of assessing the estimated damage and the resources necessary for restoration, tools to support the development of optimal weather-dependent management decisions, taking into account the probabilistic assessment of the scale of the consequences of the predicted risk. The system also integrates a standard scenario of behavior and decisions that must be made in the event of a specific combination of weather and road conditions. This is important, firstly, to reduce the influence of the human factor and incorrect assessment of the situation, and secondly, for the promptness of decision-making.
However, it is important to understand that the mere fact of having a meteorological system is not able to affect the efficiency of the enterprise. The effect of using the system largely depends on the company's strategy in the field of response to forecast dangerous hydrometeorological events. To solve this problem, it is necessary to comprehensively develop not only the meteorological content of the system, but also the methodology for using meteorological data (determining the critical values of meteorological parameters according to the degree of impact of a dangerous hydrometeorological phenomenon on infrastructure, compiling risk matrices and forecast maps of the impact on infrastructure). However, the key step that determines the success of the meteorological system is the development of a structured and comprehensive set of measures to manage weather risks, including the distribution of authority among decision makers (DMs). It should be taken into account that the inconsistency in the interaction of decision makers of different levels is an independent risk factor that increases the degree of damage from hazardous weather conditions.
The SINOP system is today one of the most modern intelligent meteorological systems, on the basis of which it is possible to create an integrated solution for managing road transport infrastructure. On the general transport map, in addition to meteorological data, it is possible to place images from photo and video cameras, traffic indicators, infrastructure facilities, information about the location of service teams and other data. Thus, all the information necessary for effective control of the situation on the roads is available in real time and in a single information system, which fully fits into the framework of the concept of building an intelligent transport system.
Literature:
1. ODM 218.8.001-2009 "Methodological recommendations for specialized hydrometeorological support of the road sector". Approved by the Decree of Rosavtodor dated November 26, 2009 N 499-r.
In this article, we will consider the features of driving a car in difficult road conditions, more precisely, in conditions of limited visibility.
What conditions for driving on the roads can be classified as difficult? For example, a clear day, visibility - to the horizon, few cars on the road, no pedestrians. This normal conditions or complex? Or, the same day, but there is heavy traffic and a lot of heavy vehicles on the road.
Or, for example, all this happens either during rain or fog. Or, worse, in the snow. It is impossible to answer unambiguously. In addition, the usual situation for an experienced driver may seem difficult for someone who has recently got behind the wheel. And that's okay.
Difficult road conditions are, in general, a combination of factors that may result in either insufficient visibility or poor vehicle controllability.
This may include
- weather conditions (rain, fog, snowfall, bright sun, ice);
- traffic conditions (large-sized vehicles: trucks, tractors with semi-trailers, buses; intersections and roadside areas with limited visibility; closed turns, lifts; objects near the road: trees, bushes, standing transport, buildings, etc.)
- in fact, the car itself (everything inside the cabin can interfere with the view, as well as the performance of individual components, such as a windshield washer, wiper, interior heater, glass heater, etc.).
All of these factors have one thing in common: in such situations, different reasons always hard to see traffic situation, i.e. we can safely say that visibility is limited or insufficient. These two phrases have different definitions(they need to be remembered for solving), but in life, in relation to traffic situations, It is the same.
Another nuisance when it rains is a puddle. Its insidiousness lies in the fact that it can turn out to be both shallow and deep, hiding a hole under it, all sorts of bumps, stones, etc. And the closer this puddle is to the side of the road, the greater the layer of dirt on its bottom. In no case do not try to overcome a puddle at high speed - you risk losing control of the steering. In addition, water may enter engine compartment, and this is fraught with problems in the electrics and electronics, up to the point that the engine can stall.
Before you enter this puddle, you must slow down in advance. And after leaving the puddle, especially if it turned out to be deep, you need to remember to check the brakes and, if necessary, dry brake pads by pressing the brake pedal several times while driving.
When it rains often and heavily, it seems that everything around seems to be immersed in fog. If this happens at night, then visibility is further complicated by the reflection of oncoming headlights from the wet road. You need to drive in heavy rain as carefully as when driving in fog. True, in the case of rain, properly working windshield wipers come to the rescue.
Wiper blades should fit snugly against the glass so that there are no blind spots on the surface, but they only work well on clean glass when enough rain water or washer fluid. Therefore, if on windshield there are traces of dried dirt (for example, from insects, if the bird did not miss, etc.), then it would be better to remove this dirt manually. Either with water, or with cleaners. If the brushes are worn out and do not do the job, they should be replaced.
Driving in heavy snow
When it goes dense snow, then the same feeling is created as in heavy rain - there is a white wall ahead, especially if the snow has already covered the ground and does not melt. What can be seen around? Shadows, contours, lights. Everything is in a fog. When the snow is heavy, the only thing you can see is the right side of the road, perhaps the center line, the parking lights of the front cars, which, by the way, will periodically be lost in the snow. Visibility, again, is poor.
What can be done to improve visibility by choosing traffic tactics? Again - slow down! Move so that it is possible in case of danger to stop within your sight. Increase your distance. Remember that in conditions of limited visibility, you need more time and space to make any maneuver and stop.
If visibility is so limited that you are not able to correctly determine the location of other road users on the roadway, it is best not to risk putting yourself and others at risk. It's better to leave the road, finding for this comfortable spot, and wait there to improve visibility conditions. Nothing urgent is worth the risk. And when you stop, do not forget to turn on the emergency alarm.
In the next article, we will consider the features.
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Clean and dry compressed air can be achieved using equipment for accurate dew point measurement. A stable dew point measurement also prevents overdrying and saves energy.
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Metrology
Vaisala offers tools and services to calibrate and ensure the proper functioning of humidity, dew point, carbon dioxide and temperature instruments. Hand-held instruments for measuring all of these parameters can be used to calibrate field instruments and as reference instruments.
Lithium battery production control
Vaisala offers a chemically resistant, polymer dew point sensor that provides long-term reliability and very low drift under heavy use. Calibrated devices that use this sensor are available as low cost transmitters or fully configurable portable instrumentation.
Semiconductor monitoring
Accurate and stable measuring devices allow you to control the microenvironment surrounding semiconductor devices.
Vaisala supplies original compact modules for measuring relative humidity and barometric pressure.
Moisture measurement of construction materials
The Vaisala HUMICAP® SHM40 Structural Moisture Meter Kit provides a simple and reliable solution for moisture measurement in reinforced concrete and other structures. This kit is for the downhole method where the tip of the moisture sensor is left in the hole until equilibrium is reached and moisture readings are possible.
Fluidized bed drying control
Precise control of the humidity of the drying air is essential to optimize the drying process. Humidity and temperature conditions may vary. In many drying processes, especially in the pharmaceutical industry, the exhaust air can have a high content of evaporated solvents and chemicals. This necessitates the use of very stable measuring instruments. In most harsh environments, the outlet of a fluidized bed dryer is considered a hazardous area where intrinsically safe instrumentation must be used.
Driving a car in adverse weather and climatic conditions
Weather and climatic conditions have a significant impact on traffic safety, especially in the autumn-winter period, when rains, snowfall and icing of the road surface significantly complicate the operation of the rolling stock and increase the likelihood of an accident. Low air temperature impairs the operation of the engine, units and vehicle components. Reduced battery performance, tire elasticity. There is a risk of water freezing and damage to the cooling system. And how many troubles the driver is given by the low coefficient of adhesion of tires to the road, limited visibility and visibility.
Peculiarities technical operation car in autumn and winter. When preparing the car for the autumn winter operation First of all, you should check the technical condition and troubleshoot. in the engine, gearbox and rear axle summer grades of lubricants should be replaced with winter grades. Otherwise, apart from increased wear units may be damaged.
The main attention should be paid to the nodes and mechanisms that directly affect traffic safety. After all, the braking qualities of the car, its controllability, the possibility of an involuntary change in the direction of movement, the supply and visibility of maneuvering signals depend on them.
It should be remembered that the smallest malfunction, which does not play a significant impact on traffic safety in summer conditions, can cause a traffic accident in winter. Especially dangerous is the uneven action of the brakes of the right and left wheels of the car. Even with light braking slippery surface this failure is fraught with dangerous consequences. Therefore, when preparing for winter operation, it is necessary to check and adjust the clearances between the drums and brake shoes. Uneven wear tire tread or differential pressure during braking also cause the vehicle to pull to one side or skid.
Ice is the most dangerous. The coefficient of adhesion of the tire to the road decreases several times and is 0.1-0.2 instead of 0.6-0.8 on dry pavement. Naturally, the forces holding the car on a given trajectory decrease by the same amount. When the vehicle is driven on dry pavement, the traction reserve remains large enough to keep the vehicle from skidding even when maximum braking or traction forces are applied. It's a different matter with ice, when a little braking or pressing the accelerator pedal can lead to a skid. On slippery road operate the steering wheel, press the clutch pedal, steer throttle valve it is necessary to smoothly apply combined braking, i.e., a service brake and an engine, which increases the braking efficiency of the car, and also helps to prevent blocking of the drive wheels.
Combined braking can be performed in a constant gear or with sequential downshifts. Since the inclusion of lower gears at high frequency Since the rotation of the crankshaft of the engine presents significant difficulties even on vehicles with a synchronized gearbox, then regassing is required to equalize the circumferential speeds of rotation of the gears involved. Since the right foot of the driver performs braking with the service brake, in order to re-gas it is necessary to temporarily stop active braking, or press the accelerator with the toe (heel) of the foot without interrupting braking with the service brake. And so that the engine does not fail, especially if downshift is turned on with a large lead in engine speed, the clutch must be engaged with some delay.
Small straight sections with ice are best driven on the move, without changing the position of the steering wheel and without braking. In no case should you give in to the reflex desire to press the brake pedal, as this can cause the car to skid.
Having determined that the car continues to move in a straight line, you should gradually reduce the engine speed and reduce the speed to safe limits. It is much more difficult to perform turns on ice. First of all, it is necessary to reduce the speed of movement in advance, using combined braking for this, then engage the desired gear and turn at low speed. It is impossible to start the car by coasting by disengaging the clutch, since when it is turned on again, a jerk in the transmission can lead to a skid. It is very dangerous, especially when turning left, to pull over to the side of the road: loose snow lying on it can cause a skid or “pull” the car into a ditch. If, nevertheless, the car has pulled over to the side of the road on one or even two sides, there is no need to rush to return it to the roadway. Frost, usually formed at the border of the carriageway and the shoulder, can cause the car to skid and turn around. Therefore, you must first reduce the speed to the required limits and only then carefully return to the roadway.
When driving on an icy road, one should not always rely on anti-slip materials that are sprinkled on the road. It often happens that the sand is not kept on the icy surface and is freely moved by the wheels of the car. Freshly fallen snow is also dangerous in ice conditions, which masks the icy coating. When braking, the snow does not roll, but moves ahead of the wheels of the car. The grip of the tires on the road is reduced, and the stopping distance of the car is significantly increased.
Particular care must be taken when driving uphill and downhill during icy conditions. First of all, it is important to correctly determine the gear in which you can overcome the slope without shifting. You should switch to this gear in advance, before the start of the ascent. If, on the selected gear, it is necessary to switch to a lower gear as quickly as possible, gradually increasing the engine speed in order to prevent the drive wheels from slipping.
For long steep descents” which often end in a narrowing of the roadway, it is necessary to turn on the third or even second gear in advance. During the descent, you must not use the coast, as the car may develop too high a speed and become uncontrollable. On a descent, intermittent braking should be applied due to the fact that the temporary termination of the brake mechanisms allows you to keep the optimal temperature regime service brake of the car, and hence its effectiveness.
When starting off on a slippery surface, the drive wheels must not be allowed to slip. Therefore, you need to touch on more high gear and at minimum engine speed, very smoothly releasing the clutch pedal. This will reduce the traction moment on the drive wheels and thereby prevent them from slipping.
Overtaking during ice is an undesirable maneuver. If, nevertheless, it is impossible to do without overtaking, it is necessary to change lanes very smoothly into the next lane, after making sure that this maneuver does not interfere with other road users. It is also necessary to return to your lane after overtaking very smoothly in order to prevent skidding.
Vehicle drift. Perhaps there is no one among the drivers who has not experienced a car skid. This trouble lurks both on wet asphalt, and in icy conditions, and on snow covered road. Brake - and the car will skid ... It is known that with a sharp skid of the car, a transverse inertial force arises. It unequally distributes the load on the right and left tires, while the springs have a different deflection. The body warps, the stability of the car decreases. Composure, sober calculation, confident actions of the driver can prevent skidding.
Let's analyze the case correct conclusion the vehicle from skidding while overtaking, detour or turning. The car skidded, say, to the left, its rear part lost direct direction movement. As soon as the driver feels the start of a skid, he must, without disengaging the clutch, reduce the fuel supply to such a limit at which the engine transmits the minimum torque to the drive wheels. In this case, it is necessary to ensure that the car is in no case slowed down by the engine, since the increasing braking forces on the wheels only increase the skid. Simultaneously with the release of gas, smoothly turn about half a turn steering wheel towards the skid, in our case to the left. As soon as the lateral speed starts to decrease, return the steering wheel to the straight ahead position. Even if the car continues to move sideways for a while, it will gradually return to a straight line. It may happen that the car turns a little in the other direction, i.e. to the right. Such a turn must be compensated by a corresponding turn of the steering wheel to the right. After several damped oscillations, the car will take a straight position on the roadway.
It should be noted that skidding on a turn with a sufficiently high qualification of the driver can be used to facilitate maneuvers. In the initial stage of skidding, it is necessary to sharply increase the engine speed, and in the future to regulate the position of the car not only with the steering wheel, but also with gas. After the skid stops, the car will turn in the direction of exiting the corner, and you can continue to move, gradually adding gas. This method significantly speeds up the recovery of the car from a skid on a turn; it can be used only after appropriate training on flat and fairly wide horizontal ice-covered areas.
The techniques for getting the car out of a skid that occurs during braking are basically similar to the methods for getting the car out of a skid on a turn. It is only necessary to remember that in case of blocking of the wheels, it is necessary to instantly loosen the pressure on the brake pedal. This is the main rule for stopping a skid, which must be constantly remembered. And then you need to act in the same way as when skidding on a turn. In winter, ruts form on some sections of the road. When driving along it, and especially when leaving it, the possibility of a sharp skid of the car is not ruled out. You should leave the track when there are no i other vehicles nearby, having previously reduced the speed. In this case, it is necessary to slightly turn the steering wheel in the direction opposite to the exit, and then vigorously turn it towards the exit.
On a well-rolled snow-covered road, you can move at a slightly higher speed than on icy roads, however, it must be borne in mind that when driving in narrow sections, the wheels may fall into loose snow lying on the side of the road. So you need to slow down.
Driving on wet and polluted roads.
In late autumn, leaves falling from trees lying on the road surface are a great danger. Once on such a site, the driver of a car moving at high speed, if necessary, braking, may lose control and end up in a ditch or in the oncoming lane, since the leaves under the wheels of the car can play the role of lubricant, sharply reducing the friction coefficient of one or more wheels. To prevent this from happening, it is necessary to assess the situation at a greater distance than on a dry road and anticipate its possible changes, which will allow you to slow down in a timely and fairly smooth manner.
In autumn and spring, the road surface is often not only wet, but also dirty due to intensive agricultural traffic. Although a wet, contaminated pavement is less dangerous than an icy one, however, it should be taken into account that the coefficient of adhesion of wheels to the road on a wet asphalt concrete pavement decreases by 1.5-2 times compared to a dry one, and dirty and oily - by 4 times. In the same ratio, the braking distance of the car also increases.
The onset of rain is especially dangerous for drivers. The first drops do not wash off, but only moisten the road dust and dried dirt, turning them into a "lubricant", which significantly reduces the effectiveness of the brakes. .Experienced driver feels the movement of the machine that after a long and heavy rain, the coefficient of adhesion increases slightly. This is the result of the slippery film being washed off the road by streams of water. In rainy weather, sections where secondary unpaved adjoin the main asphalt road are especially dangerous. Soil dirt applied by people, vehicles or livestock can play a fatal role.
Driving on a wet road is also dangerous because water, getting on brake pads significantly reduces the effectiveness of the brakes. Therefore, when driving through large puddles and during heavy rain, you should periodically check the operation of the brakes while driving. If the brakes are wet, then they need to be dried by adding gas, and slowing down with your left foot. When the driver feels that the brakes have been restored, he can continue with normal driving.
Sometimes in the rain, a very dangerous phenomenon can occur - hydroplaning. Its essence lies in the fact that at a sufficiently high speed and a large thickness of the water film, a water wedge appears in the contact zone of the tires with the road, tearing off the wheels of the car from the coating. The car, as it were, crouches on the rear wheels, while the front wheels rise on a water wedge. The car stops listening to the steering wheel, although rear wheels continue to maintain traction. For this reason, even on straight sections, the vehicle suddenly finds itself in the oncoming lane, and on curves it suddenly pulls over or rolls over. A layer of water several millimeters thick causes hydroplaning at speeds over 80 km/h. Therefore, experienced drivers, when driving through areas flooded with water, adhere to a speed of no more than 60-60 km / h.
Hydroplaning depends on the thickness of the water film, the quality of the pavement surface, the volume of water, the presence of transverse grooves on the pavement, the tread pattern of the tire, the specific pressure in the contact zone, vertical and lateral loads.
It should be noted that hard tires modern trucks better destroy the water cushion, the effect of hydroplaning begins only at. speeds of 120-140 km / h, i.e., practically unattainable for them, and more elastic passenger car tires destroy the water film only at speeds up to 60-80 km / h.
Not knowing about the existence of the effect of hydroplaning, some drivers explained this state of the car (in which the brakes do not “grab”) simply by oiling the pads or poor operation of the brake drive (not pushing the working fluid).
It is difficult to teach a driver to determine the starting point of hydroplaning, but knowledge, experience, a desire to understand and find safe methods of driving a car will help in this.
wind load. In autumn, strong winds often rise. Therefore, the driver must be aware of the features of driving a car associated with wind load.
The strength of the wind is not constant either in magnitude or in direction.
The most unpleasant for the driver is a strong lateral wind load. Suffice it to say that at a wind speed of 25 m/s, an additional lateral force of about 300 kg acts on a Zhiguli car, and more than 1,600 kg on a LAZ bus. On slippery and icy surfaces at high speeds, such a force can move the car. A skid may begin.
Under the influence of lateral wind load, the tires deform due to their elasticity, and the car deviates from a straight path. The driver must compensate for this deviation by turning the steering wheel, and the car will remain straight, moving with the front wheels turned at some angle. With a sharp increase or decrease in wind strength, it is necessary to maintain the desired direction of movement in a timely manner, by small turns of the steering wheel. In places where a sharp gust of crosswind can deviate the vehicle from rectilinear movement, a warning sign 1.27 "Sidewind" is installed.
The main safety measure when driving on such sections of roads is to reduce the speed of movement.
| Vladimir |
