A child pedestrian was taken to hospital with serious injuries after being in collision with a car in Corfe Mullen.
Police were called to the B3074 Blandford Road, near to the junction with Ridgeway, yesterday afternoon at 4.22pm.
The car involved was a white Smart ForTwo.
Road closures were put in place to allow the emergency services to respond and for an examination of the collision scene to be carried out.
Officers are appealing for witnesses or anyone with relevant dashcam footage to contact them.
Sergeant Dave Cotterill, of the traffic unit, said: “We are conducting a full investigation into the circumstances of this collision and I am appealing for any witnesses who have not already spoken to police to please get in touch.
“I would also urge any motorists who were in the vicinity with dashcam fitted to please review their footage to see if they have captured anything of relevance.
“Finally, I would like to thank motorists for their patience and understanding while the road closures have been in place.
“These are absolutely necessary to enable the emergency services to respond and for a detailed examination of the scene to be carried out.”
Anyone with information is asked to contact Dorset Police at www.dorset.police.uk, via email at scit@dorset.pnn.police.uk or by calling 101, quoting incident number 17:396.