Police are appealing for information following a serious road crash in Mixenden on Sunday afternoon.
Three people were injured, including a five-year-old and a 44-year-old man, who were taken to Leeds General Infirmary by air ambulance.
Another male driver, aged 32, was taken to Huddersfield Royal Infirmary by ambulance.
The incident happened on at around 1:50pm on High Lees Road, when a yellow quad bike was involved in a crash with a black Suzuki motorbike.
Emergency services were in attendance and the road was closed while they worked at the scene.
Anyone with any information about this incident, or who saw either of the vehicles prior to the collision is asked to contact the police via 101 quoting log number 0788 of 26/03.