Low speed working condition. When a car is driving on a city road, the closest working condition is low speed. This is because the traffic on urban roads is large and the speed is slow, so cars need to start, accelerate, slow down and stop frequently. These operations consume fuel and energy, and also produce waste gas and noise. Low-speed working condition refers to the working state of the automobile when it is driving at a low speed, generally referring to the situation that the vehicle speed is below 20km/h..