Bahrain barrier behaved 'exactly as it was supposed to', says circuit designer

“Concrete blocks can deflect energy and they are not going to be broken. Guardrails [on the race track] are stiffer than what you might find on the highway, but it’s still elastic, it’s still deformable.

“The whole point of the guardrail is that it fits inside the ground and should bend the poles, because otherwise it is like a wall.

Zaffelli pointed to further evidence of the guardrail acting as predicted: “On the video footage, you can see there is a cloud of sand one or two frames after the first impact. The first pole that was just bending itself, absorbing energy, and as a result vaulting dirt into the air.”

Circuit designers use a range of barriers to cope with the most likely set of collisions. In braking zones, soft and padded layers are used to absorb as much energy as possible when cars hit them head-first.

But alongside the track, where cars are running parallel, the angle of impact is likely to be much shallower, and it’s safer to allow a car to slide along a relatively rigid surface than to get caught up in a softer one.

“Grosjean’s accident was very unusual,” said Zaffelli. “It’s highly unlikely that you would have cars going almost full speed at that kind of angle into that kind of barrier. The kind of angles you normally have there, it’s better to have something which deflects – but it can only deflect so much.

“You would like the barrier to remain intact as possible, but at some point, when the energy it’s too much, it will break. It’s physics.”

He said that Formula 1 witnessed a similar situation five years ago when Carlos Sainz’s Toro Rosso speared into the barriers at 93mph in a braking zone. On this occasion, he first hit foam-filled TecPro blocks lined up in front of the barrier.

“What we saw [in Bahrain] is something that has been seen already several times,” said Zaffelli. “Probably nobody remembers because it was behind the Tecpro, but think back to Sochi ‘15 when Sainz went into the Tecpro – the guardrail on the back actually collapsed.”

However, in Grosjean’s case, there was no layer in front of the barrier because it was running alongside the track. As the barrier deformed, a gap was wedged open between the horizontal guardrails attached to the metal poles in the ground, known as blades, leading to the horrifying images of the front half of the Haas lodged in the barrier, at the centre of a fireball.

It was an unusual, unlucky set of circumstances, said Zaffelli, at a part of the circuit where cars are usually accelerating straight out of a corner.

“The guardrail is supposed to contain the impact with the poles, not with the blades,” he said. “The fact is that Grosjean went into the barrier at an angle of approximately 40 degrees, sliding on the left. When it was sliding it hit the first pole.

“The first pole bent as he hit it, and as soon as he did, it inclined the guardrail, and as soon as this happened it started to rip off the blades.”

“The car glided down the side and then started to go between the blades. The survival shell was extremely rigid and penetrated the barrier because the speed was very fast, which widened the gap between the blades. Then another pole ended up between the survival cell and the back of the car.”

“I think if there is something to look at which can be improved, it is not on the barrier. I’m sure that the barrier was designed correctly and mounted correctly.

“I’m sure the FIA will do a full investigation on this, but I would be quite surprised if they would find something that is not at the level required by the FIA for the guard rails.

“Then there is another discussion – is it better to have guardrails instead of concrete? But I would say that generally yes they are good.

“If you want something which is stiffer than you have to go with the SAFER Barrier which is used on ovals. The SAFER barrier is something which is not collapsing like that, because it is mounted on an elastic mounting, which allows the barrier to deform and then jump back to the original point.

Zaffelli said the chances of Grosjean hitting the guardrail and opening it up in the way he did was so slim, he is unsure if changing the angle of the barrier would improve safety. He does not expect the barrier to be altered for this weekend’s Sakhir Grand Prix, which uses the same section of track.

“You have to appreciate that the accident that happened to Grosjean could happen anywhere in any other form,” he said. “You have to think about whether crashes are likely or not, predictable or not. This is an accident which can happen anywhere.

“Just on the basis of this accident, [changing the guardrail] should not be done.

“The accident actually started 200 metres before the eventual crash. The accident happened because there was a heap of cars, normally this doesn’t happen.

“We need to reduce the angle of impact but if the car is spinning, if it’s going very fast and very well placed to break…the same crash could occur again.”