A bus driver is in a serious but stable condition after his vehicle crashed into a tree on Adelaide’s O-Bahn track on Thursday morning.

The incident occurred just after 9.30am at the end of the track in Modbury, thankfully with no passengers on board.

Witnesses described hearing a loud bang and seeing a large cloud of dust before observing the aftermath of the crash.

The driver was trapped inside the mangled bus, prompting a careful extraction operation by emergency services.

“The driver was stabilised by paramedics and then we used our specialist tools to remove the bus from the driver,” said Shane Finney of the Metropolitan Fire Service.

The 27-year-old driver was rushed to hospital and remains in a serious but stable condition.

Major crash investigators are still piecing together the cause of the accident, which caused significant delays to O-Bahn services.

The track was closed between Paradise and Tea Tree Plaza for seven hours, only reopening after the damaged bus was removed from the scene.

The incident has raised concerns about safety on the O-Bahn, with some passengers expressing shock and disbelief at the severity of the crash.

Authorities are urging the public to remain patient as investigations continue.