Speeding, poor driving by an unqualified driver and lax supervision are to blame for last month's school bus accident that killed 15 pupils in the eastern city of Xuzhou, an investigation report said yesterday.

The main factor in the December 12 crash was that the bus - carrying 47 pupils - was traveling too fast, said the report issued by the Office of Work Safety Commission of the State Council.

The speeding vehicle overturned into a ditch to avoid hitting a pedicab in Fengxian County.

In addition to the fatalities, eight pupils were injured.

Investigators also found that while the driver held a driving license, it did not permit him to drive buses.

And the probe said the driver failed to act properly in trying to avoid the pedicab.

The accident has also revealed a lack of supervision on school bus management and road safety. The office will announce punishments for those held responsible for the accident, the report said.

Following the accident , families of the 15 children killed were told that they would receive about 502,000 yuan (US$78,760) compensation for each child. But many refused to take the cash until they saw the report.

Meanwhile, four drafts issued by the Ministry of Industry and Information Technology of China last week on the safety conditions for school buses have proved controversial with many bus manufacturers.

Some questioned whether the standards, drafted by a team led by an official from a major bus manufacturer Yutong Co, could help the company monopolize the school bus market, according to local newspaper 21st Century Business Herald.

"These strict standards all relate to advanced bus products by Yutong," an industry insider told the newspaper.

"In the bus manufacturing industry, few other companies are able to meet these standards," the insider said.

And some manufacturers said that while buses meeting new standards may be safer, a sharp rise in the costs - estimated at 30 percent by some - would prove a major problem for poorer provinces.