Bangkok metropolis has been the capital of Kingdom of Thailand for more than 220 years. as Bangkok has been every kind of center of the country. whether in economy , trading investment education politics governing including culture has made this grow-up very fast. however; Bangkok has to face many problems which obstruct their development especially the traffic problem since the number of cars have been continuously increased the roads are limited that effected most to economic system environment and standard of living as year go by many ways of effort in traffic improvement have been applied especially the construction of roads or express ways but it seemed to be a consecutively non-stopped problems of increasing number of cars at present the mass transportation as electricity train has been widely accepted as the most significant transportation in many large cities of the world.