All means of transportation do not emit the same amount of carbon dioxide per person per mile traveled. A rough estimate of the amount of carbon dioxide emitted by a person traveling a 1000 miles is:
- 206 kg if a small car is used
- 414 kg if a large car is used
- 86 kg if a train is used
- 48 kg if a bus is used
- 276 kg if a plane is used
Therefore, it can be seen that the cleanest means of transportation are bus and train. This is largely to do with the fact that here many people are accommodated in the same vehicle. Cars are the worst polluters, especially if they are used with just a single person on board. Planes also pollute a lot due to the nature of the technology that is used for flying.