The breath-taking rise of Bangkok to become a leading business center in Asia created a basic challenge for the city to ensure the mobility of millions of people. Before 1999, people used to take a bus, motorcycle or taxi for almost 80 per cent of their daily travel needs. This created congestion in large parts of Bangkok's infrastructure, making traffic jams a daily occurrence. The travel speed in downtown Bangkok was usually less than ten kilometers per hour. This not only affected the mobility of the commuters but had also an impact on the quality of life. Without a working rapid transit and mainline traffic concept, Thailand's capital was bound to grind to a standstill.