Please help me correct my article. Thanks a lot!!! In my opinion, three main factors lead to this trend. Firstly, there is an increasingly number of vehicles existing in cities and towns since people tend to accumulate enough wealth to afford private vehicles. At the meantime, the prices of cars decrease significantly and private vehicles are not yet a kind of luxury for most middle Class. Secondly, in these decades, more and more people immigrate to cities and towns from countryside, which definitely lay a heavy burden on public services, traffic included. Finally, there are many cities which were not organized properly-when they were established-with a result that these places become overcrowded