Police are appealing for witnesses following a road traffic collision in Armley.
Officers would like to speak to anyone who witnessed the incident on Branch Road at about 2pm this afternoon.
It occurred after a Mercedes Sprinter van was in collision with a black Seat Ibiza while in slow-moving traffic.
Officers believe the 70-year-old driver of the Sprinter suffered a medical episode – believed to be a heart attack – at the wheel.
He is now being treated in hospital where he is described as being in a serious but stable condition.
The incident led to long delays in the Armley area.
Anyone who saw the incident or the vehicles just prior to the collision is asked to contact PC 5979 David Webster at SRANS East on 101.