Sajjad Ahmad, 37, died in Forth Valley Royal Hospital in Larbert on Tuesday night following the collision between a white Vauxhall van and his silver Mercedes on the M9 in West Lothian at about 9pm on Friday.
Mr Ahmad’s wife Saadia, also 37, and their nine-year-old daughter Ayesha died at the scene along with van driver Mark Hansen, 42.
The Ahmads’ two sons, aged 10 and 14, were also injured and remain in a serious condition in hospital, Police Scotland said.
Officers are continuing to investigate the cause of the crash and appealed for witnesses to the collision on the southbound carriageway of the M9 between Polmont and Linlithgow.
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Sergeant Scott Sneddon said: “Our sincere condolences go to the Ahmad family, who have asked that their privacy be respected at this tragic time.
“Our enquiries continue to establish the full circumstances surrounding this collision and I’d like to thank the witnesses who have so far come forward.
“Anyone who witnessed the collision, saw either of the vehicles shortly beforehand or has any information about this and has not yet been in contact is urged to get in touch.
“Anyone with information can contact Police Scotland on 101 or make an anonymous report through the charity Crimestoppers on 0800 555 111.”