After the invention of automobiles from the 18th century till the 21st century, the majorities of people all around the world have started to prefer using fuel-powered vehicles to horses, chariots, or walking because it is believed that driving a car can show the high social status in the society and that owning as many cars as possible can show the wealth to the public. Many people have adopted these two ideas that it has poisoned their minds not to think of the adversely underlying impacts on the environment, human health, and traffic problems However, a number of environmental scholars who are concerned about the bad impacts have considered the reduction of private vehicles with the introduction to public transportation. In favor of the increasing trend for private vehicles, public means of transportation buses, trolleybuses, trams and trains, and rapid transit including metro, subways or underground (Wikipedia, 2015), should highly be encouraged to be open for the public in Cambodia for three major reasons: to prevent global climate change, to avoid health repercussion, and to cut down traffic issues in the society.
One of the beneficial factors to promote public transportation in Cambodia is that it helps prevent the climate change from occurring in a very fast pace. That the vehicles produce smoke consisting of largely carbon dioxide (CO2) is widely known to the world, and its adverse effects to the environment are very critical. When there is more and more carbon dioxide in the atmosphere, it surely will result in the global warming because of the rising temperature that is caused by the "greenhouse" effect. The greenhouse effect is one of the greenhouse gases that result from carbon dioxide, and it acts as a blanket covering the earth to trap the temperature at the highest degree. As Hare mentions, increasing the CO2 concentration in the earth's atmosphere effectively adds another blanket which warm the earth's surface even more (as cited in Laffel, 2006, p.
