Four elements of transportation.

People, vehicles, roads and traffic environment.

1. people: including drivers, pedestrians and passengers, are the main body of transportation activities.

2. Cars: including various means of transportation, such as cars, trains, ships, planes, etc. , is the carrier of transportation.

3. Roads: including all kinds of roads, bridges and tunnels. These are all transportation channels.

4. Traffic environment: including the social, economic and natural environment in which traffic and transportation activities are located, is an important external condition for traffic and transportation activities.