6. Glossary

Speed; vitesse

A vehicle's speed is defined as the distance it covers per unit of time. Most of the time, each vehicle on the road will have a somewhat different speed from those around it. In road traffic quantification, the average speed of traffic is the significant variable. The average speed, known as the spatial average speed, can be found by averaging the individual speeds of all vehicles in the study area.

Vehicle concentration; volume

Volume is simply the number of vehicles passing a given point on the roadway in a specified period of time. By counting the number of vehicles passing a point on the roadway during a 15-minute period, you can arrive at the 15-minute volume. Volume is usually converted directly to flow rate q, which is a more useful parameter.

Débit; flow