Police are appealing for witnesses and information after a collision near Lewes.
The collision involving two vehicles happened on the B2116 near Plumpton College at about 8.30pm on Tuesday, September 24.
It involved a Nissan Micra and a Kia Venga.
The driver of the Nissan, an 18-year-old man from Hailsham, and a passenger, an 18-year-old woman from Ringmer, sustained serious injuries.
They were taken to the Royal Sussex County Hospital in Brighton, where they remain.
Two other passengers in the vehicle, an 18-year-old man from Adversane and an 18-year-old woman from Arundel, sustained minor injuries and attended the same hospital.
Officers are investigating and want to speak with anyone with relevant information about the collision.
This includes witnesses or anyone with CCTV or dashcam footage of the collision of the vehicles in the area prior to the collision.
Information can be reported to Sussex Police online or on 101, quoting Operation Longridge.
