Road condition analysis of MATLAB racing car

When a motor vehicle is driving on the expressway and the speed exceeds 100 km, it shall keep a distance of 100 m or more from the vehicle in front of the same lane. When the vehicle speed is lower than per hour100km, the distance from the vehicle in front of the same lane may be shortened appropriately, but the minimum distance shall not be less than 50m.

It should be noted that in rainy and snowy weather, in order to ensure the safety of driving on ordinary roads, it is desirable to increase the distance between cars, but it is not suitable in expressway. Because on the expressway, the speed of vehicles is generally more than 60 kilometers per hour. When encountering special weather such as rain, snow or road icing, the braking distance of the vehicle is extended by 1.5 ~ 3 times than normal due to the decrease of road adhesion coefficient. In such a long braking distance, the possibility of accidents such as vehicle deviation, side slip and tail flick will be greatly increased. At the same time, when there is a lot of water on the road surface, there may be a dangerous "water film phenomenon" between the wheels of the driving vehicle and the road surface, that is, the wheels completely lose direct contact with the road surface and float on the surface of the water, just like water skiing, and then the steering and braking operations completely fail. Whether the "water film phenomenon" occurs during the driving process of the vehicle can not be discovered by the driver himself in time, but only when the steering or braking fails, which is quite dangerous. The "water film phenomenon" is related to the driving speed, and will begin to appear when the driving speed exceeds 80 kilometers per hour.

Therefore, in bad weather such as rain and snow, when driving on expressway, the first safety measure should be to slow down properly. In order to prevent "water film phenomenon", the speed should be reduced to below 80 kilometers per hour. At the same time, in order to keep enough distance between cars, the distance between the rear car and the front car should be kept at 2 ~ 3 times the speed of the car after proper deceleration.