Updated, Tuesday 4pm: An investigation is underway after a serious crash between a white Mitsubishi ute and a bicycle on Cambridge Road around 3:20pm.
Preliminary investigations indicate the rider of the bicycle, a 12-year-old boy, rode from Paige Court and unsuccessfully attempted to turn right onto Cambridge Road, before drifting onto the roadway and colliding with the passenger side of the utility.
Police say the boy was not wearing a helmet at the time of the collision .
He was rushed to the Royal Hobart Hospital with serious head injuries, where he remains in a critical condition.

The driver of the ute was not injured.
Police have thanked ‘several’ good samaritans who offered assistance and first aid to the boy.

The road re-opened around 6:30pm after investigators spent three hours combing the scene.
Anyone with information or relevant dash cam footage is being asked to contact police.
Updated, Tuesday 4pm: The cyclist is being transported by Ambulance to the Royal Hobart Hospital for medical treatment.
Their injuries are reported to be serious, while the road remains blocked.
Earlier: A serious crash involving a vehicle and a cyclist has blocked a major Hobart road this afternoon.
Emergency services were called to Cambridge Road at Warrane around 3pm on Tuesday.
The road is currently closed and diversions are in place at Bruny Street and Zeehan Street.
Police said details of injuries are not yet known but the incident is understood to be serious.