One man has died and five people have been injured following the crash which brought the M8 to a standstill on Saturday.
The crash near the Shotts junction on Scotland's busiest motorway happened around 3.30pm.
An air ambulance was called to the scene, while the road was closed in both directions for hours.
An Audi A4 which was heading west crashed into the central barrier, ending up in the eastbound carriageway where it hit a Subaru Impreza which was heading in the other direction.
A 44-year-old man who was a passenger in the Audi died at the scene, while the 25-year-old driver and a 21-year-old passenger were slightly injured.
The 27-year-old man who was driving the Subaru also had slight injuries however his two female passengers, aged 29 and 26, were badly injured.
They are being treated at the Royal Infirmary of Edinburgh. Medics say they are in a serious but stable condition.
Sgt Jon Mochan, based in the road policing complex in Glasgow, is appealing for witnesses.
Anyone with dash cam footage of the incident has been urged to contact police immediately via 101 quoting incident number 2953 of 27 July.
The crash led to delays for many people heading to the Elrow Town dance music festival at the Royal Highland Centre in Ingliston.
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