English 
the speedometer of an automobile reads
1. Speedometer: As shown in the car, each small grid indicates 5km/h, and then you can read it by looking at the position of the pointer, as shown in the picture, it is 65km/h.
2. Stopwatch: There are two long and short pointers, the long one indicates 30S, and the short one indicates minutes, just add the indications of the long and short pointers together.
The indication of the speedometer depends on the vehicle speed sensor. The sensor is installed on the gearbox. Through different speeds, different pulse signals are obtained, and then converted into pointer output, which is the current speed you see. Regulations require that the speedometer display should be higher than the actual speed. Slightly higher, this is for safety. There is also a liquid crystal display speed, the principle is similar to the above, indicating that the output is replaced by a liquid crystal display.The car stopwatch has a certain error. When the car stopwatch shows 60 yards, the non-contact speedometer shows that the actual speed is 53.2 yards. When the car stopwatch shows 80 yards, the non-contact speedometer shows that the actual speed is 72.9 yards. The stopwatch shows 60 yards, and the actual speed is 53.2 yards.
The car's speedometer represents the current driving speed of the vehicle. It is calculated based on the wheel speed sensor on the drive axle. It is calculated based on the wheel diameter of the vehicle when it leaves the factory and is calculated with a preset formula. It is an estimated value rather than an accurate value. If the vehicle's tire size changes, or the diameter of the wheel changes due to wear, the speed displayed on the vehicle's dashboard will be slightly inaccurate, but the difference will not be significant. Generally speaking, the real speed of the vehicle is 2-4 km/h lower than the speed displayed on the dashboard. Speedometer is an application for checking the speed of travel and supports two units: miles per hour or kilometers per hour. The speedometer function requires strong GPS signal support and can display a maximum speed of 220 km/h.
1. If there are two lanes in the same direction, the minimum speed of the left lane is 100 kilometers per hour;
2. If there are more than three lanes in the same direction, the minimum speed of the leftmost lane is 110 kilometers per hour, and the minimum speed of the middle lane is 90 kilometers per hour;
3. There are only four fast lanes in the same direction. The first lane on the right is the truck lane, the speed cannot be lower than 60, the second lane is the truck overtaking lane, the speed cannot be lower than 80, the third lane is the bus lane, the speed cannot be lower than 100, the first lane on the left It is an overtaking lane and cannot be lower than 110.
4. The expressway should indicate the driving speed of the lane, the maximum speed shall not exceed 120 kilometers per hour, and the minimum speed shall not be lower than 60 kilometers per hour;
5. The maximum speed of small passenger cars driving on the expressway shall not exceed 120 kilometers per hour, the maximum speed of other motor vehicles shall not exceed 100 kilometers per hour, and the maximum speed of motorcycles shall not exceed 80 kilometers per hour.
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