The driver of a tour bus which overturned at Km5.8 of the Kuala Lumpur-Seremban Expressway here yesterday had committed three traffic offences previously, police said.

Kuala Lumpur traffic investigation and legal affairs officer DSP Shafie Daud, when contacted by Bernama today, said one of the offences was obstructing traffic.

"A urine sample of the 42-year-old driver has been sent to the Chemistry Department and the results will be out soon.

"The driver has been released on police bail," he said.

The bus skidded and overturned at about 9am yesterday, injuring 37 passengers. It was carrying 44 people aged between 50 and 70 from Ampang to Puchong.