The second reason cars are popular is the fact that (1)__________________________________. Long-distance trains have never been as common in the United States as they are in other parts of the world. Nowadays there is a good system of air-service provided by planes. (2)____________________________. The third reason is the most important one, though. The American spirit of independence is what really made cars popular. Americans don't like to wait for a bus, or a train or even a plane. (3)___________________________. A car gives them the freedom to schedule their own time. And this is the freedom that Americans want most to have.