HUALIEN - Speeding was to blame for a traffic accident on Taiwan's rugged east coast Friday evening that has left 30 mainland tourists and one local tourist guide injured, local police said Saturday.

A tour bus is seen rolled over on Taiwan's Highway No 11, which connects Hualien County and Taitung County, in Hualien County, February 17, 2012.?[Photo/Xinhua]?

The bus was traveling at 93.5 km per hour, nearly twice the 50 km per hour limit on the highway, a spokesman with the Hualien police bureau said.

Low visibility caused by rain and the drivers' lack of knowledge of road conditions also were factors which lead to the accident, leaving at least nine passengers in serious condition, according to police.

Thirty-four people were onboard at the time of the accident, including 32 mainland tourists en route to a Peking opera exchange trip, a Taiwan's driver and a local tourist guide.

The driver and two passengers have been discharged from hospital.

Injuries sustained vary from broken pelvises to brain hemorrhages. At least two passengers were in comas, according to doctors.

Some of the hospitalized have contacted their mainland relatives and their medical bills will be covered by insurance.

The accident took place at 6:15 pm Friday when the bus heading northward crashed into a wall and rolled at the 43 km point of the Taitung-Hualien coastal road, police said.

The mainland travellers have been identified as a group involved in a Peking opera exchange program. They were invited by a Taipei-based Chinese opera institution.

The group arrived in Taiwan on February 14, and was scheduled to leave on February 20.

The driver is currently under police investigation.