Automobiles and Undergrounds

Along with the rapid development of the modern society, more and more forms of transportation have been invented, such as bicycles, motorcycles, buses, trains, high-speed rails and so on. But to my mind, the most two convenient ways we used frequently in our daily lives are automobiles and undergrounds as they are the most popular ways people choose.

These two forms of transportation are similar in that they both need a lot of iron and steel be used to produce as raw materials. Furthermore, both of them are energy consumption transportations. They cannot work without energy.

Although the two forms of transportation consume energy, the power sources they consume are quite different. The sources of automobiles are petrol, that which is rare and nonrenewable. Recent data shows that when petrol is used as a fuel, the emission rate of carbon dioxide is 0.916 pounds per mile and the annual pollution emitted will reach 11,450 pounds. Other exhaust gases from the automobiles such as carbon monoxide, sulfur dioxide also emitted as well. Obviously, because of the power sources the automobiles consume, they are become the major contributors to air pollution. By contrast, undergrounds are much more environmental as they consume the electricity----a renewable resources which can be reproduced by using technologies. In contrast, undergrounds can work well without any exhaust emission. That really makes a contribution to the environment.

The capacity of each car is 4 people in general, while undergrounds are high-capacity transportation. Clearly, the latter is much more efficient than the former. Because the low-capacity of automobiles, the demand are rapid increased in recent years with lower and lower price. Increasing number of automobiles lead more and more traffic jams. This phenomenon brings not only emission pollution but also noise pollution. The noise of the horn an automobile makes is about 80-100 decibels. Undergrounds, however, never have the problems of traffic jams for their schedules are always punctual. Furthermore, they do not make any noise at all.

Both automobiles and undergrounds are popular forms of transportation. The automobiles are easy moved and convenient, while the undergrounds are punctual and cheap. Form the point of view of environmental protection, automobiles produce more pollutions than the undergrounds. But if we can utilize the transportations in a correct way, our lives will