cause of traffic congestion in Bangkok is due to the whole city plan and public transportation services, which are unsuitable to meet the rapid growth of Bangkok and surrounding areas. For the city plan, the concerned authorities in the past failed to enforce concerned laws to promote the effectiveness of the proposed city plan, while mass transportation networks are quite scarce. This is to say that the present commuter train lines, both BTS and MRT, do not reach every corner of Bangkok. This is why more and more Bangkokians are dependent on private cars instead of public services.