According to eyewitnesses, the bus did not speed but moving steadily with approximately 90km/h at middle lane. The Chinese couple, Ms. Lu (makeup artist) and Mr. Xu (businessman) was driving about 100 meters behind the bus before the horrific accident happened. Both of them claimed that the bus steered a bit to left before it lost control and crashed to the opposite expressway. Note: I translated the couple's names from Chinese.
They suspect a car moved from fast lane to middle lane out of sudden and the bus was trying to avoid the car but failed and eventually lost control.
Green car was the eyewitnesses' car,
while X was the car suspected to be the cause of accident.
The bus driver's wife said her late husband was a careful driver, it's very unlikely that he over-speed and put others' life on risk. According to a reliable source, the deceased's daughter gets a lot of calls and messages accusing her father as murderer.
People, if you read this I beg you to spread this because he was innocent. He should not be called a murderer and his family should not be disturbed this way.
source: http://chinapress.com.my/content_new.asp?dt=2010-10-13&sec=malaysia&art=1013ma13a36.txt