Highways England said: "Traffic is stopped in both directions on the A1 between the A639 and B6474 near Barnsdale Bar due to two separate multi vehicle collisions. Traffic officers and emergency services are on scene and dealing. There is approx four miles of congestion in both directions."
"The southbound carriageway was partially blocked following a collision involving three vehicles and the northbound carriageway was blocked following a collision involving four vehicles.
"Officers from the West Yorkshire Police Roads Policing Unit attended the incident which was reported at around noon.
"A number of injuries have been reported. None are believed to be life threatening."
A lane has now re-opened in both directions.