An incident has closed the A422 in both directions near Milton Keynes.
The closure is in place between the Old Stratford Roundabout and the junction with Stratford Road in Passenham near Deanshanger.
Traffic is also queuing in the nearby area as motorists seek alternative routes.
The A422 is one of the main routes between the northern part of Milton Keynes and nearby towns of Buckingham and Bicester.
One motorist posted on social media stating they had been turned around on the approach to the closure.
It is not yet known if there are any injuries as a result of the incident.
