As the name suggests, this classification number is used to distinguish various models. In fact, we only need to see the first number on the left to tell the two cars apart. From 0 to 9, different numbers represent different vehicles, and the meanings of these numbers are more complicated. (For cars before 1999, this position ranged from 1 to 3 digits. Since 1999, three digits have been fully implemented.)

3: Ordinary passenger car. Models with a nuclear load of less than 11 and a displacement of more than 2.0.

4/6: Small cars. A passenger car carrying less than 10 people, or a small truck used to carry goods. The general size shall not exceed 4.7x1.7x2.0 meters, and the displacement shall not exceed 2.0L.