Officers, investigating a road traffic collision near Sutton Coldfield, are appealing for witnesses.
A 23-year-old man was left with potentially life threatening injuries after coming off a quad bike shortly before 9pm on Tuesday 15 June at Carroway Head Hill.
He remains in hospital at this time and his family are being supported by specially trained officers.
Officers from the Staffordshire and West Midlands Serious Collision Investigation Unit are now urging anyone with information or dashcam footage to come forward.
Anyone with any information should message Staffordshire Police on Facebook or Twitter quoting incident number 741 of 15 June, call 101 or alternatively contact Crimestoppers anonymously on 0800 555 111.