Police are appealing for information following a serious road traffic collision on the A58 Rochdale Road, Halifax on Saturday 30 November.
The collision happened at around 7.40pm and was involving a white Vauxhall combo van and a blue Peugeot Partner Tepee car.
The Vauxhall van was travelling in the direction of Sowerby Bridge and the Peugeot was travelling in the direction of Ripponden.
The driver of the van, a man in his 30s, was seriously injured in the collision and remains in hospital.
Anyone with information or anyone who witnessed either vehicle driving in the area prior to the collision is asked to contact police.
Officers would also like to hear from anyone who may have dashcam footage of the collision or of either vehicle.
Anyone with information is asked to contact the Roads Policing Unit on 101, quoting log 1580 of 30/11.