The woman who is in her eighties is in a serious condition following a collision in Calderdale earlier this month.
Police are appealing for information about the collision which occurred at around 12.40pm on Monday 4 September on Milton Avenue, in Sowerby Bridge.
A multicoloured Optare Solo bus was travelling in the direction of Albert Road when it was in collision with a stationary Ford Transit van.
The impact of the collision caused the bus to cross to the other side of the road where it collided with a tree. The bus then collided with a parked Landrover Discovery vehicle.
A passenger on the bus, a woman in her 80s, received treatment for minor injuries at the time of the collision. Her condition has since deteriorated and she is now in hospital in a serious condition.
Anyone who witnessed the collision or anyone who saw the bus driving in the area prior to the collision is asked to contact the Safer Roads team.