A man has been arrested on suspicion of causing death by careless driving after a fatal crash on the M4 in Berkshire.
Three vehicles were involved in the crash, between junction 13 at Newbury and junction 12 at Reading, eastbound, just before 14:00 BST on Friday.
A 73-year-old female driver from Wales died at the scene. Her 74-year-old male passenger was taken by air ambulance to hospital with serious injuries.
The arrested man, 40, from West Sussex, remains in police custody.
Police are appealing for any witnesses to the crash, which shut the motorway eastbound on Friday until 21:30.
The three vehicles involved were a white Astra van, a black Land Rover Freelander and a white Audi A3.
The woman who died was driving the Land Rover. No-one else was injured, Thames Valley Police said.
Sgt Darren Brown said: “Our thoughts at this time remain with the families of those affected by this collision.
“An investigation has started and we would like to hear from anyone who has information which could help.”