Traffic is a collection of things coming and going in a particular loacation. Most commonly on earth it refers to people or information. When in reference to people, the people are often using a vehicle to move them faster than they could walk or run. Although when you get enought vehicles in one place (in this case automobiles), it almost inevitably produces a traffic-jam (which is not nearly as yummy as the strawberry jam you put on your toast). In which case it would probably be faster to get out and walk. Trafic-jams produce high levels of stress and iritability. This can be observed by the honking of horns and hand guestures and in some extreme cases, weapons. Beware of getting too close to a truck with the markings such as "Guns don't kill people, I do" or "Pardon my driving, I'm reloading". Often, these vehicles contain people known as rednecks. Keep your distance.
The traffic of information is much the same as traffic of people, only the information moves through wires, fiber optics, or satallite signals. Information traffic-jams can also produce high levels of stress and irritability, but you usually don't have to worry about rednecks pulling out a shotgun when your computer is too slow.