Many drivers do not always bother to familiarize themselves with the information contained directly on the tires they purchase, as a result of which their operation will not meet the recommended parameters and will quickly fail. Meanwhile, the data indicated on the tires must be carefully checked with the indicators technical characteristics car. Indicators such as tire size and type, speed and load indexation are the main indicators of the purchased product.
The tire speed index is a value indicating the maximum speed with a normal load on 1 wheel. It is determined by kilometers traveled per hour and is indicated by letters from A-Z on the side of the wheel. The index is calculated only by the manufacturer and if there is no designation on the tires, the maximum speed should not exceed 110 km/h.
When determining the tire speed index, there is a decoding of the letter indicators, which contributes to the right choice rubber for a specific car, delimited by speed data, quality and structure of the rubber. There are also double indexing designations that allow you to use tires in more wide range. Tires with a speed rating of “ZR” can only be used on autobahns with an approximate V = 240-400 km/h.
Decoding the speed index
It is important to know that the speed index is closely related to the tire load index when determining the permissible load at maximum speed and is designated by a digital equivalent. This index greatly influences the service life of the tire and the nature of traffic. A low tire load index allows the car to drive smoothly and silently, while a high load index does the opposite, but at the same time the service life of such a tire is quite long.
Tire load index decoding table
| Index | 70-80 | 80-90 | 90-100 | 100-111 |
| Weight (kg) | 335-450 | 450-600 | 600-800 | 800-1090 |
Effect of load on the speed index
The tire load indicator shows the weight that is maximum permissible at the maximum speed of the vehicle, therefore these two indices are interrelated and must be taken into account when purchasing them. Let’s say V auto > 240 km/h and is indicated by the index “W”, then the maximum load should be limited and reduced by 3 percent for each subsequent 10 km/h. If the load indexing and speed do not match, the use of rubber can lead to its rupture, deformation of the wheel and the entire suspension as a whole.
Features of using the speed index
Every car enthusiast should know that decoding speed index shows the speed at which the tire will retain its characteristics. And when choosing tires for both passenger cars and truck it is always necessary to take this indicator into account, since it is this indicator, together with the load index, that has big influence on traffic safety.
Tire Load Index- an important parameter that you need to pay attention to when choosing car tires. The tire load index marking is located on the sidewall of the profile and is indicated as a digital value. What does the tire load index mean? For example, 215/65 R16 98T, the digital marking “98” indicates that the load capacity or load index of the tire is 750 kg.
Tire load index table
The designation of the tire load index is indicated in the marking by a combination of numbers. The tire load table below shows all load index values in accordance with their symbol.
Tire Load Index Table with explanation
For passenger cars a rubber load index of 60 to 125 is used, or, in other words, from 250 kg to 1650 kg. Both small cars and large SUVs fall within this framework.
What does the maximum tire load index mean?
The maximum load index on tires (maximum load per tire in kg) means that the tire can withstand a certain load at the maximum permissible speed, which is marked as the maximum tire speed index.
How to calculate the tire load index for a car?
To correctly calculate the load index indicated on the tire, it is necessary to multiply it by the number of vehicle tires (usually 4), and subtract the curb weight of the vehicle and the weight of the driver and passengers from the resulting value. As a result, the resulting difference will be the value of the free carrying capacity of the vehicle. In other words, the result will be the weight that can be placed in the car without reducing safety when driving at a speed determined by the speed index of the tires used. Let's look at a specific example of how to calculate the tire load index on a car.
For example, tires 215/65 R16 98T, where 98T is the load and speed index marking. Load index “98” corresponds to a load capacity of 750 kg per wheel. We multiply 750 kg by the number of wheels (for example, 4), we get 3000 kg of total load capacity. Now from 3000 kg we subtract the weight of the car (for example, 1500 kg), the weight of the driver (let's say 90 kg) and, for example, 3 passengers with a total weight of 200 kg, we get a difference of 1210 kg, the potential weight of the cargo that can be evenly placed in the car without reducing the level of safety when maximum speed “T” index of 190 km/h.
Load index is the maximum permissible value, which it is better not to approach when operating the car. It is necessary to take into account the fact of how and where the cargo will be placed in the car. Generally, the most popular place to place cargo is in the trunk, with the bulk of the load on rear axle or in other words, on 2 wheels. Based on this, you need to calculate Weight Limit cargo in the trunk. How to calculate the tire load in this case? In the example above, the maximum cargo weight for the car turned out to be 1210 kg, but if you load the trunk, then the maximum possible cargo weight will be at 600 kg, and for safe movement- no more than 450kg. If the load index is as close as possible to the recommended values or if it is exceeded, tires may wear out faster and become deformed under shock loads on uneven roads. Using the maximum possible load, relative to the load index, at the highest possible speeds, relative to the tire speed index, is UNSAFE!
Tire load index decoding
Decoding the tire load index is possible only thanks to special tables, such as “Tire load index decoding” () or with the help of consultants from car tire stores, who must provide any information of interest on the product offered. Choosing suitable tires, it is necessary to pay attention to the fact that the higher the tire load index is from that recommended by the car manufacturer, the less driving comfort remains due to the increase in rigidity and strengthening of the tire sidewall to withstand the weight determined by the load index. It is also not worth underestimating the wheel load index recommended by the car manufacturer; in this case, the comfort of movement will be greater, but the level of passive safety will be reduced.
When choosing car tires, people don’t often pay attention to one thing: the most important parameter characterizing the speed properties of rubber - tire speed index. It is an official indicator and has its own typology and labeling.
Tires must always meet the main requirement: they must correspond to the characteristics of the car, including speed.
If a car moves at a speed of 140 km/h, then it cannot be equipped with tires designed for a maximum speed of 110 km/h. This is fraught with major and minor troubles: from an accident to an emergency “change of shoes” for suddenly deteriorated tires. Therefore, it is necessary to know the speed parameters of the tires you are purchasing.
Kilometers per hour limit
Speed index is an indicator indicating the maximum speed permissible speed car with which it can travel with these tires. It is marked on the side of the tire with a Latin letter.
Simply put, manufacturers tell customers: on this tire you can drive at such and such a maximum speed. If you exceed, then don’t be offended: there will be deformation, destruction of rubber and other unpleasant things.
The specified limit must not be exceeded. But this does not mean that the tires will fly into rags as soon as they reach the maximum permissible kilometers per hour. During actual operation, the condition of tires is affected by many factors, such as current load, temperature, weather, road surface condition, etc.
This indicator limits the maximum permissible speed under normal load and in the case of a fairly long trip. If a car drives for 10-15 minutes at a speed of 155 km/h on tires designed for 140 km/h, then nothing bad will happen. If such a ride is longer, then the effect of rubber destruction is possible.
For trucks The rule applies: if the load on the tires increases (that is, when there is a load), then the permissible maximum speed decreases, and can be 80-90% of the set index. After tire repair, during long-term use, this figure also decreases by 10-15%.
It is not necessary to know these nuances thoroughly if the driver clearly understands the speed characteristics of his car and selects the appropriate tires. In any case, having bought tires with the letter T (up to 190 km/h), you can not worry and drive calmly, without violating traffic rules.
Parameter description
Tables are usually used to decipher the tire speed index. Marking in Latin letters is assigned by the manufacturer based on test results of this type tires It is applied to the side of each tire during manufacture.
| Index | Maximum speed, km/h |
| A1 | 5 |
| A2 | 10 |
| A3 | 15 |
| A4 | 20 |
| A5 | 25 |
| A6 | 30 |
| A7 | 35 |
| A8 | 40 |
| IN | 50 |
| WITH | 60 |
| D | 65 |
| E | 70 |
| F | 80 |
| G | 90 |
| J | 100 |
| K | 110 |
| L | 120 |
| M | 130 |
| N | 140 |
| P | 150 |
| Q | 160 |
| R | 170 |
| S | 180 |
| T | 190 |
| U | 200 |
| H | 210 |
| V | 240 |
| W | 270 |
| Y | 300 |
| VR | 210-240 |
| Z | Over 240 |
Indices from A1 to A8 provide for a maximum speed of 5 to 40 kilometers per hour, and letters from B to G, respectively, 50-90 km/h. The limit of 100 km/h is indexed by the letter J. Then, in increments of 10 km/h, there are letters from K to T (excluding the letter O). If there is a U on the side of the tire, it means the limit is set at 200 km/h. Then come H, V, Z (over 240 km/h), then W. The letter Y determines the limit of 300 km/h.
If there is no designation, then the default tire speed setting should not be more than 110 km/h. Sometimes there is double indexing, which shows a wider range of exploitation. For example, the ZR marking denotes high-speed tires for highways - up to 400 km/h.
Decoding the corresponding speed index does not require much effort to remember. It is enough to know that modern passenger cars do not drive at a maximum of 100 kilometers per hour, and in most cases (taking into account traffic regulations) rarely exceed 180 km/h. This means that the range of tire speed indices narrows and is limited by markers from K to T. The most suitable tires for modern cars are marked H, Q, R, S, T, U, Z.
Tire Load Index
| IN | KG | IN | KG | IN | KG | IN | KG | IN | KG | IN | KG | IN | KG |
| 0 | 45 | 40 | 140 | 80 | 450 | 120 | 1400 | 160 | 4500 | 200 | 14000 | 240 | 45000 |
| 1 | 46,2 | 41 | 145 | 81 | 462 | 121 | 1450 | 161 | 4625 | 201 | 14500 | 241 | 46250 |
| 2 | 47,5 | 42 | 150 | 82 | 475 | 122 | 1500 | 162 | 4750 | 202 | 15000 | 242 | 47500 |
| 3 | 48,7 | 43 | 155 | 83 | 487 | 123 | 1550 | 163 | 4875 | 203 | 15500 | 243 | 48750 |
| 4 | 50 | 44 | 160 | 84 | 500 | 124 | 1600 | 164 | 5000 | 204 | 16000 | 244 | 50000 |
| 5 | 51,5 | 45 | 165 | 85 | 515 | 125 | 1650 | 165 | 5150 | 205 | 16500 | 245 | 51500 |
| 6 | 53 | 46 | 170 | 86 | 530 | 126 | 1700 | 166 | 5300 | 206 | 17000 | 246 | 53000 |
| 7 | 54,5 | 47 | 175 | 87 | 545 | 127 | 1750 | 167 | 5450 | 207 | 17500 | 247 | 54500 |
| 8 | 56 | 48 | 180 | 88 | 560 | 128 | 1800 | 168 | 5600 | 208 | 18000 | 248 | 56000 |
| 9 | 58 | 49 | 185 | 89 | 580 | 129 | 1850 | 169 | 5800 | 209 | 18500 | 249 | 58000 |
| 10 | 60 | 50 | 190 | 90 | 600 | 130 | 1900 | 170 | 6000 | 210 | 19000 | 250 | 60000 |
| 11 | 61,5 | 51 | 195 | 91 | 615 | 131 | 1950 | 171 | 6150 | 211 | 19500 | 251 | 61500 |
| 12 | 63 | 52 | 200 | 92 | 630 | 132 | 2000 | 172 | 6300 | 212 | 20000 | 252 | 63000 |
| 13 | 65 | 53 | 206 | 93 | 650 | 133 | 2060 | 173 | 6500 | 213 | 20600 | 253 | 65000 |
| 14 | 67 | 54 | 212 | 94 | 670 | 134 | 2120 | 174 | 6700 | 214 | 21200 | 254 | 67000 |
| 15 | 69 | 55 | 218 | 95 | 690 | 135 | 2180 | 175 | 6900 | 215 | 21800 | 255 | 69000 |
| 16 | 71 | 56 | 224 | 96 | 710 | 136 | 2240 | 176 | 7100 | 216 | 22400 | 256 | 71000 |
| 17 | 73 | 57 | 230 | 97 | 730 | 137 | 2300 | 177 | 7300 | 217 | 23000 | 257 | 73000 |
| 18 | 75 | 58 | 236 | 98 | 750 | 138 | 2360 | 178 | 7500 | 218 | 23600 | 258 | 75000 |
| 19 | 77,5 | 59 | 243 | 99 | 775 | 139 | 2430 | 179 | 7750 | 219 | 24300 | 259 | 77500 |
| 20 | 80 | 60 | 250 | 100 | 800 | 140 | 2500 | 180 | 8000 | 220 | 25000 | 260 | 80000 |
| 21 | 82,5 | 61 | 257 | 101 | 825 | 141 | 2575 | 181 | 8250 | 221 | 25750 | 261 | 82500 |
| 22 | 86 | 62 | 265 | 102 | 850 | 142 | 2650 | 182 | 8500 | 222 | 26500 | 262 | 85000 |
| 23 | 87,5 | 63 | 272 | 103 | 875 | 143 | 2725 | 183 | 8750 | 223 | 27250 | 263 | 87500 |
| 24 | 90 | 64 | 280 | 104 | 900 | 144 | 2800 | 184 | 9000 | 224 | 28000 | 264 | 90000 |
| 25 | 92,5 | 65 | 290 | 105 | 925 | 145 | 2900 | 185 | 9250 | 225 | 29000 | 265 | 92500 |
| 26 | 95 | 66 | 300 | 106 | 950 | 146 | 3000 | 186 | 9500 | 226 | 30000 | 266 | 97500 |
| 27 | 97,5 | 67 | 307 | 107 | 975 | 147 | 3075 | 187 | 9750 | 227 | 30750 | 267 | 97500 |
| 28 | 100 | 68 | 315 | 108 | 1000 | 148 | 3150 | 188 | 10000 | 228 | 31500 | 268 | 100000 |
| 29 | 103 | 69 | 325 | 109 | 1030 | 149 | 3250 | 189 | 10300 | 229 | 32500 | 269 | 103000 |
| 30 | 106 | 70 | 335 | 110 | 1060 | 150 | 3350 | 190 | 10600 | 230 | 33500 | 270 | 106000 |
| 31 | 109 | 71 | 345 | 111 | 1090 | 151 | 3450 | 191 | 10900 | 231 | 34500 | 271 | 109000 |
| 32 | 112 | 72 | 355 | 112 | 1120 | 152 | 3550 | 192 | 11200 | 232 | 35500 | 272 | 112000 |
| 33 | 115 | 73 | 365 | 113 | 1150 | 153 | 3650 | 193 | 11500 | 233 | 36500 | 273 | 115000 |
| 34 | 118 | 74 | 375 | 114 | 1180 | 154 | 3750 | 194 | 11800 | 234 | 37500 | 274 | 118000 |
| 35 | 121 | 75 | 387 | 115 | 1215 | 155 | 3875 | 195 | 12150 | 235 | 38750 | 275 | 121000 |
| 36 | 125 | 76 | 400 | 116 | 1250 | 156 | 4000 | 196 | 12500 | 236 | 40000 | 276 | 125000 |
| 37 | 128 | 77 | 412 | 117 | 1285 | 157 | 4125 | 197 | 12850 | 237 | 41250 | 277 | 128500 |
| 38 | 132 | 78 | 426 | 118 | 1320 | 158 | 4250 | 198 | 13200 | 238 | 42500 | 278 | 132000 |
| 39 | 136 | 79 | 437 | 119 | 1360 | 159 | 4375 | 199 | 13600 | 239 | 43750 | 279 | 136000 |
Experienced car owners pay attention not only to the manufacturer, but also to several important factors, among which the first place should be given to tire speed and load indices.
To understand what a tire speed index is, you need to know the definition of this concept. In fact, this indicator provides for a specific standardized speed mode that determines the practical operating range of the tire. To find out the speed index of a particular tire, just look at the surface of the wheel; there should be a Latin marking on the side. This indicator is determined by just one letter, corresponding to the speed compatible with the use of a certain type of tire.
When choosing tires, it is very important to pay attention to their characteristics.
The indices located on the side of the wheel have a close relationship, since the first indicator directly characterizes the load value provided for the nominal value, and the second determines the maximum valid index speed.
Today, on the Internet you can find many web sources that will help you easily determine the tire speed index for any car, which will be helped by a specialized table. Among other information, it contains speed indicators that are slightly larger than the index itself. According to this, every car owner must purchase only those tires that are indicated in the car documents. The seriousness of this decision is emphasized by the fact that a special label must be placed on which the speed index for the tires of a particular vehicle must be indicated. This required condition has been in effect for several years now foreign countries. By indicating the nominal index on the label, the driver of the car undertakes not to exceed.
Buying tires depending on the speed index
Any of the tires available for sale today has a certain category, on which the tire speed index depends. Having bought it at least once for your vehicle tires, the car owner will know that first of all attention should be paid to the data that is carried directly by the surface of the wheel. By studying this type of information, the vehicle owner becomes familiar with the speed index, expressed in numerical equivalent.
According to the pattern located on the tread, they are divided into winter, demi-season and summer tires.
Indicators of all types of tires
If a car owner is interested in purchasing exclusively winter tires, he should know how wheels of this type are marked. On winter tires The speed index H is always present in combination with the letters M+S. It is important to remember that on winter version The wheels' tread pattern is brighter and deeper.
Demi-season tires are characterized by a different speed index, since tires of this type allow the car owner to confidently drive a vehicle at almost any time of the year; on demi-season tires, the car should easily go on wet asphalt and dry road.
Rubber for the warm season has its own characteristics. This type of tire is not equipped with any micropattern, due to which a more dense grip is achieved. road surface. Speed index summer tires higher than the typical indicator for demi-season and winter wheels.
Tire size
Owners vehicles Before purchasing new tires, you should study certain information, which concerns, in particular, the tire size. This definition means special system labeling that is valid internationally. Paying attention to any wheel, you can see on the side, for example, the inscription 185/75 R15 82S.
The decoding of this inscription is very simple: a certain car has a tire width of 185 mm; 75 mm - an indicator characterizing the distance between the tire width and the profile height; the Latin letter R indicates that the product has radial cord. The number 15 denotes the wheel diameter, the letter S denotes the speed index, which does not allow the driver of this car to accelerate more than 180 km/h, and the number 82 denotes the load index.
As mentioned above, before buying the tires you like, you should definitely look at the car’s operating manual and find out the tire speed index that should be located on the tires for a particular vehicle.
Basic Facts About Tire Load Index
The indicator discussed in this part of the article means maximum load, expressed in numerical equivalent, which the tire can withstand. Thanks to this characteristic, every vehicle owner will know about speed limit, which should not be exceeded at a specific air pressure in the wheels.
However, you should not assume that even if the load value is slightly exceeded, the tire will be torn into several parts. All modern tires have permissible excess, thanks to which the load can be increased by no more than 20–30%.
The decoding of the load index depends on the class indicated on the tire:
- the Latin letter Y warns of a speed limit not exceeding 270 km/h;
- letter W - about the limit of 240 km/h;
- owners of tires with the letter V can only accelerate to 210 km/h.
However, if, due to certain circumstances, the owner of the tire regularly has to exceed these indicators, the maximum load index should be mandatory downgraded Sometimes there are tires belonging, in particular, to the ZR class, on the surface of which such properties are not indicated. In this case, the car owner will have to contact the car manufacturer to determine the maximum load value.
Features of the European standard
The commission determining the various European standards, the ECE-R54 regulation has been adopted, according to which all tires in the world used on vehicles for commercial transportation are equipped with a certain type of marking: such tires must bear the inscription Service Description (translated as operating conditions).
The inscription is always located in close proximity to the tire size. The marking represents special code, which implies the maximum allowable value of the load index. It should be noted that this property determines the load index for both single and double wheels. At the same time, the marking provides a speed index, which looks like, for example, 102/100R.
These two indicators, which determine the maximum load and speed, are stamped on the wheel on both sides. The first indicator regulates a specific tire at the time of its installation, and the other - the maximum load that can fall on dual wheels. Sometimes, in addition to all of the above, an additional type of characteristic is used that determines the load at the highest speeds.
Seasonality of tires
The tire load index, as it became clear from the above material, means the maximum permissible speed indicator, which directly depends on the carrying capacity of the vehicle. It is this characteristic that determines the utmost permissible weight for those cars.
Deciphering any indicator printed on the side of the rubber does not take more than 2-3 minutes for those car owners who are well familiar with speed loads, tire seasonality and all types of markings. Sometimes, next to the tire size, its seasonality is indicated, for example, the word Tubeless means the need for beading on a disc without a tube.
Wise choice of tires
Absolutely every modern car owner is concerned about the condition of his vehicle, therefore, when choosing any component, he is especially careful about the quality of the product. One of the most important purchases for your car is the purchase of tires, no matter what season it is purchased for, it is important to make the right and most informed decision, on which in the future the safety of not only the car owner, but also all passengers will depend.
The choice of tires should in no way depend on the year of manufacture of the vehicle, the country of origin and the load capacity of the vehicle. Naturally, these factors can be taken into account, but you must rely solely on the recommendations specified in the instruction manual. Equally important when choosing are the conditions in which you plan to use the purchased product (city, off-road, highway), the driving style of the owner of the vehicle, seasonality and technical features of the car.
The speed index in question determines the maximum weight limit that goes on only one wheel. In view of this, one should not ignore the fact that the weight of the car is most often unevenly distributed between the front and rear axles.
This circumstance must be taken into account when purchasing tires; the car owner must provide some reserve, equal to a quarter of a fully loaded car. The thickness of the frame depends on the increased coefficient, the elasticity of which will correspondingly decrease.
In addition, you should know that all the factors described are closely related to car depreciation, smooth passage road unevenness and potholes. The safety factor negatively affects comfortable movement and rapid wear pendants. The optimal coefficient should correspond to 30–35% of the vehicle’s curb weight.
How important is it to make the right choice?
Tires purchased from car dealerships or car markets must cope perfectly with many loads that correspond to technical features a certain car. The maximum load should be considered to be the one at which the rubber can withstand the impact, measured in relative units (varying from 60 to 125 units). These indicators can be seen on the beads of tires designed exclusively for one wheel.
Trucks naturally have their own tire speed index, which is indicated for a single wheel or a pair of tires. In the latter case, the indicator will be divided by the digital value of the fraction.
What can happen if a car is equipped with tires with inappropriate tire indexes?
Car manufacturers under no circumstances recommend installing tires on cars for which the tire speed index does not correspond to that provided by their manufacturer. The fact is that if the indicator is less than the established one, the owner of the vehicle may have huge troubles, since the tires while driving may simply not withstand the load placed on them.
Otherwise, if the indicator only slightly exceeds the required value, the installation of such tires may be allowed. For example, you can take a tire with an XL or RF load index.
Conclusion
When choosing tires for his car, the car owner must clearly understand the seriousness of the purchase he is making. Before making a choice, you must definitely study the car’s operating manual, find out about the recommended tire load index and other indicators regulated by the manufacturer.
If you purchase inappropriate tires, the driver may not have the best experience. pleasant surprises. Most likely, a tire that cannot withstand the load will have to be changed urgently right in the middle of the road. Even if the tire does not break into several pieces, the resulting troubles can delay a hurrying driver for a long time.
Modern car tires have markings on the outer side surface (on the visible part of the product) that give an idea of the characteristics of the operating conditions of the rubber. This is required by the ECE-R54 standards adopted in Europe. The main task of the mentioned designations is to maintain balance while using tires. One of the most important designations is the tire speed index, which we will talk about later.
What is the speed index?
Among the values indicated on the sidewall of the tire is the speed index, which is closely related to the load-lifting coefficient. Decoding this parameter comes down to limiting the speed of a vehicle moving at maximum permissible load for a long time. In other words, by indicating the index, the manufacturer guarantees you that nothing will happen to the tire when accelerating to the specified speed value.
The speed index of a tire, as well as the load capacity indicator, is usually placed immediately after the tire size marking. For example, the designation 205/55 R16 91V will mean that the tire is characterized by:
- Width 205 millimeters.
- The height is 55 percent of the width.
- Radial cord arrangement.
- Planting diameter 16 inches.
This is followed by , expressed by the number “91”, and the speed index marking in the form of the Latin letter “V”. In the example given, the value “V” indicates the vehicle speed limit is 240 km/h (see table). Please note that failure to comply with the specified speed limit will most likely result in increased impact centrifugal forces, which will cause resonance and vibration while driving. Of course, this is very unsafe, since it can cause an accident due to the destruction of the wheel.
For each tire model, the manufacturer determines the speed index by processing data obtained during testing of the tire on a special stand, using various power and speed loads. The speed index was introduced not only for safety reasons. It also allows tire manufacturers to differentiate tires into groups, depending on characteristics, for example, by rubber quality, cord structure, etc.
Tire Speed Index Table
Below is a table showing all existing speed index designations and their meaning. 
Separately, we note that the last “ZR” value is slightly different from the others. Tires with this marking are intended for use on highways at speeds exceeding 240 km/h. There is also a "VR" index, not listed in the table. Tires with this marking are designed for speeds exceeding 210 km/h.
In conclusion, let us remind you that the car must move at a speed that is 10-15 percent lower than that specified by the tire manufacturer. This counts correct use tires Otherwise, they may not withstand the load, which will lead to the destruction of the structure. So choose tires taking into account all the nuances, this will provide not only high level comfort, but also maximum driving safety.
