The N4 has reopened following a serious five-vehicle collision this morning and all diversions have been lifted.
The incident occurred on the Longford side of the Castlepollard exit between 9.30am and 10am.
Locals said a truck, which was travelling from Dublin towards the west, went out of control and crossed over to the other side of the road just after passing junction 11 on the Mullingar bypass.
It then collided with another truck heading in the opposite direction.
Three more cars were struck as the two vehicles tried to stop.
The driver of the west-bound truck was trapped in his vehicle for almost an hour and was seriously injured.
He is now in a critical condition at the Midland Regional Hospital.
Three other people who were treated for minor injuries have been released.
