A woman died and her eight-year-old daughter was critically injured when their car left the road and landed in a ditch.
It happened on the westbound carriageway of the A35 Upton Bypass in Poole, Dorset, at about 20:50 GMT on Friday.
The silver Vauxhall Astra crashed just before the Baker’s Arms roundabout, police said.
The 28-year-old woman’s daughter was airlifted to hospital.
The A35 was closed in both directions, and Dorset Police is appealing for witnesses or anyone with dashcam footage to come forward.