Jenson Button has revealed that he analysed a lot of data before he decided that it was safe for him to drive his McLaren, in the wake of Fernando Alonso's crash.
Button's teammate crashed into a wall during the second pre-season test in Barcelona, and spent three nights in hospital with concussion.
The cause of his crash is still a mystery, and some reports had suggested that the Spaniard received an electric shock from the car, which prompted Button to investigate.
He told reporters: "I will not get into a car unless I am 100% sure it is safe. I spent hours going through the data with the engineers and talking to them about the incident. I trust these guys and that is why I have the confidence to drive it this weekend.
"I needed to know that before getting into the car at the next test so I made sure of it. When you are driving a Formula 1 car at the limit you need to be sure."
The 2015 season gets underway this weekend in Australia.