A 60-year-old man was airlifted to hospital following a crash south of Aviemore.
The A9 was closed in both directions following the collision at around 1.45pm on Tuesday.
Police, ambulance and the fire service all rushed to the scene of the two-vehicle crash near to Lynwilg.
The male driver of a blue Skoda Octavia, aged 60, was taken by air ambulance to the Queen Elizabeth University Hospital in Glasgow.
Medical staff have described his condition as “critical”.
Another two units and a critical care paramedic were also dispatched to the scene.
The 17-year-old driver and sole occupant of a Toyota Hilux pick-up was taken to Raigmore Hospital where he remains in a “stable” condition.
An ambulance service spokesman said: “We received a call to attend a road traffic collision on the A9.
“We dispatched two ambulances, an air ambulance and a critical care paramedic to the scene.”
Witness appeal following A9 crash near Aviemore
A fire service spokesman said: “We were alerted at 1.58pm on Tuesday to reports of a road traffic collision at the A9 road, south of Aviemore.
“Operations Control mobilised three appliances to the scene .”
The road was reopened by 9.30pm.
Police are now appealing for anyone who witnessed the crash to come forward.
Sergeant Calum Macaulay, from the roads policing unit in Dingwall, said: “I am keen to hear from anyone, not yet spoken to by police, who was on the road and either witnessed the crash or who has dash-cam footage of the incident.”
Anyone with information is asked to call police on 101 quoting incident number 1712 of March 5.