Alfa Romeo team principal Frédéric Vasseur has revealed the force of Zhou Guanyu's British Grand Prix crash was around twice that of the FIA's crash tests.
The roll hoop of Zhou's Alfa Romeo appeared to fail at Silverstone after his C42 was flipped upside down on the run to turn one.
Before a car can be raced, its roll structure must pass several stringent tests, including absorbing a 105kN [kiloNewton] vertical load.
Although Alfa Romeo is still investigating the crash and subsequent damage, Vasseur said: "The crash was something like two times more than the load of the crash test.
"It meant we dug a groove on the Tarmac for something like four, five metres.
"It doesn't matter the level of the crash tests, you can always find something a bit bigger and, for sure, we have to take action on our side and with the FIA to improve the safety.
"But at the end of the day, I want to stay positive and to say after a big crash, nothing happened.
"Thankfully we had no fuel leak on the car because this would have been by far the worst-case scenario. Can you imagine what the outcome would have been if there had been a fuse?"
Vasseur "wrong" with halo criticism
Vasseur was a critic of the halo when it was introduced ahead of the 2018 season but after Zhou's crash, he was forced to concede he has long since changed his opinion.
"He [Zhou] came back to the garage one hour after the crash when he was released from the medical centre and he had absolutely nothing [wrong with him]," said Vasseur.
"His first question was about the stock of parts for Spielberg and for sure, a couple of days later when you think about this, it is just incredible to have such a huge crash and to come back to the garage and be focused on the next one.
"It's unbelievable. On this, it's thanks to the FIA, thanks to the safety criteria.
"I was not the biggest fan of the halo at the beginning, but I was wrong and last week between Zhou and the F2 crash [Roy Nissany], it's thanks to the FIA."
Additional reporting by Ian Parkes