Spanish female Formula One test driver Maria De Villota was taken to hospital with life-threatening injuries after her Marussia car hit a parked truck at an airfield in eastern England.
The Marussia team said in a statement that De Villota, who was testing the car for the first time, was injured after completing an installation run at Duxford airfield at around 0810 GMT.
"Maria has been transferred to hospital. Once her medical condition has been assessed a further statement will be issued," the team added.
East of England ambulance service spokesman Gary Sanderson said in a separate statement that the driver had "sustained life-threatening injuries" and was at Addenbrookes Hospital in Cambridge.
BBC Cambridgeshire presenter Chris Mann, who was at the Imperial War Museum-owned airfield for the straight-line test, said the car "inexplicably accelerated" into the back of the team's parked support truck.
"The driver's helmet was impacted on the side of the truck," he reported. "It just happened suddenly, a very shocking incident.
"The car slowed down as you see happens during a Grand Prix, for it to then be reversed into the pits which was actually a tent. But at the last second it just suddenly accelerated again so by the time it hit the truck, it was doing 30 or 40 miles an hour."
Mann said De Villota, 32, was trapped in the car for a considerable time with emergency services attending her immediately.
"It appeared to me that she wasn't moving for about 10 or 15 minutes. We saw her move her hands after about a quarter of an hour and it took almost an hour for the ambulance (staff) to feel confident to take her out of the car."
The driver is the daughter of former F1 racer Emilio De Villota.
She was appointed test driver of Russian-licensed Marussia in March, making her the only woman in such a role at the time although Williams have since handed a similar development role to Suzie Wolff.
De Villota has raced in various series and tried out a Renault Formula One car last August.
Marussia's race regulars are German driver Timo Glock, who missed the last Grand Prix in Valencia through illness, and Frenchman Charles Pic.
The team have no reserve driver and De Villota lacks the necessary super-licence for the role.