The definition of traffic volume is 1. The definition of traffic volume refers to the number of traffic entities passing through a certain place, a certain section or a certain lane in a selected period of time. 2. The characteristic traffic volume is a random number, and the traffic volume at different time and place is different. The phenomenon that traffic volume changes with time and space is called the temporal and spatial distribution characteristics of traffic volume. 3. Representation traffic volume is constantly changing, and the average value of a certain time period is usually taken as the representative traffic volume in representation. If the unit is vehicle/day, the expression of average traffic volume is: