Police have arrested a man on suspicion of drug driving in Herefordshire.
It follows a serious collision on the A49 between Harewood End and Much Marcle.
Detectives said that a man has been arrested on suspicion of driving under the influence of drugs.
The road remains closed for investigation work.
A spokesperson for West Midlands Ambulance Service said: "A man was found to have suffered serious injuries in the collision and received specialist trauma care at the scene before being airlifted to Southmead Hospital, Bristol.
"A woman was treated for injuries not believed to be serious before being taken to Hereford County Hospital."