Police Scotland road policing officers are in attendance on the A71 west of the Lizzie Bryce roundabout near to Dedridge, Livingston after a serious road traffic collision involving two vehicles.
The collision happened around 1.40 pm today.
The A71 has been closed eastbound from Newpark roundabout, Livingston and westbound at the Lizzie Bryce roundabout.
A man and two women have been taken to the Edinburgh Royal Infirmary for treatment for serious injuries.
The road will be closed for several hours to allow collision investigations. However vehicles can still access the A71 traveling west from the Crofthead interchange.
Anyone who witnessed the collision is asked to contact police on 101.