F1 halo: what the bar over the cockpit is for and the crashes it helped in

What is the halo?

The halo is a bar over the cockpit that protects the driver’s head. It is fixed to the car at three points: one mount at the front and two at the back.

In the technical regulations the halo is called the secondary roll structure. There are two roll structures, and both are there to protect the driver if the car turns over: the principal one stands behind the driver’s head, and the halo sits over the cockpit. The halo itself is not considered part of the monocoque. It is a standard component: it is made to an FIA standard and supplied by manufacturers designated by the FIA, which makes sure that halos from different suppliers weigh about the same.

The standard component doesn’t include the front mounting bracket or the fairing. A team may fit a fairing to the halo, but it has to stay within the volume set by the regulations. How the rest of the 2026 car’s protection works, including the principal roll structure, the nose and the side structures, is explained in the article on the 2026 car.

When did the halo become compulsory?

From the 2018 season. According to Formula 1, drivers began calling for protection against flying wheels and debris after Felipe Massa’s injury in F1 and the deaths of Henry Surtees in Formula 2 and Justin Wilson in IndyCar.

By 2017 the FIA had spent five years developing and testing different protection systems, among them a reinforced plastic windscreen in front of the driver. In testing, an F1 wheel and tyre were fired at the cockpit. The FIA concluded that the halo gave the best overall protection.

According to Formula 1, the bar met with fierce opposition at first: people disliked its looks and the move away from the open cockpit that had always been part of single-seater racing. The criticism mostly faded once the halo had possibly saved several drivers’ lives.

What is it made of and how much does it weigh?

Titanium alloy. The FIA set out the requirements in standard 8869-2018. The titanium version is made from Ti6Al4V Grade 5 alloy, and the whole assembly must weigh 7.0 kg, with a tolerance of minus 150 to plus 50 grams. The standard also describes a steel version that is almost twice as heavy, at 13.5 kg.

According to Formula 1, the championship uses the titanium halo. The regulations fix its position on the car precisely: the front mount at a set point on the car’s centreline, the rear mounts at a set height, and the whole structure symmetrical.

What load can the halo withstand?

Under the FIA standard, halo samples go through two tests at 125 kN, about the weight of a 12.7-tonne load, before approval. In the first test the halo must not break or deflect by more than 17.5 mm under that load. A minute after the load is released, the permanent deformation must be less than 3 mm. In the second test it must not break before 125 kN or deflect by more than 45 mm up to that load, and it must absorb at least 7 kJ of energy.

The halo mountings on the monocoque are tested separately. Under the 2026 technical regulations there are two static tests with a load of 140 kN:

The load is built up in under three minutes and held for five seconds. A team may instead load the mountings partially, to 57% or 71%, and show by calculation that they would take more than 120% of the test load, which is 168 kN.

The requirements used to be lower. Under the 2021 technical regulations, the mountings were loaded with 116 kN downwards and 46 kN rearwards on the centreline, and 93 kN inwards and 83 kN rearwards from the side. When the halo was introduced, Mercedes’ James Allison explained that the monocoque had to be strengthened to take roughly the weight of a London double-decker bus resting on the halo.

Which crashes did the halo help in?

Below are the cases that the FIA or Formula 1 directly link to the halo. Race results are from the f1db database.

2018, Belgium: Charles Leclerc

At the 2018 Belgian Grand Prix, Nico Hülkenberg locked his front wheels under braking for the first corner and hit Fernando Alonso’s McLaren. Alonso’s car was launched into the air and flew over the Sauber of Charles Leclerc. The McLaren left clear marks on the right-hand side of Leclerc’s halo. Neither Alonso nor Leclerc was hurt. Leclerc said the halo had probably helped him. All three retired on the first lap.

2020, Bahrain: Romain Grosjean

On the first lap of the 2020 Bahrain Grand Prix, Romain Grosjean touched Daniil Kvyat’s car at 241 km/h (150 mph) and lost control. The Haas hit the barrier, the monocoque pierced it and the car caught fire. Grosjean got out by himself after 27 seconds.

According to the FIA investigation, the helmet, HANS, harness, monocoque, seat, headrest and halo all performed as their specifications require. They protected the space around the driver and coped with the forces that acted on him in the impact. From his hospital bed, Grosjean said that a few years earlier he had been against the halo, but without it he wouldn’t be able to talk now. How many g the impact produced is explained in the g-force article.

2021, Italy: Lewis Hamilton

At the 2021 Italian Grand Prix, Lewis Hamilton had just come out of the pit lane when Max Verstappen tried to pass him around the outside in the first chicane. The cars collided, and the Red Bull was thrown into the air and came to rest on top of Hamilton’s Mercedes. The Red Bull’s right rear wheel hit Hamilton’s helmet, but the halo took the car’s weight, so the blow wasn’t a heavy one. Hamilton escaped with a sore neck and said the halo had saved his neck. Both retired.

Formula 1 also counts another case from that year, at the Emilia Romagna Grand Prix. There Valtteri Bottas collided with George Russell, and the Williams reared up and hit the side of the Mercedes cockpit.

2022, Great Britain: Zhou Guanyu

At the start of the 2022 British Grand Prix, the car of Zhou Guanyu turned upside down. According to the FIA, the halo was credited with protecting the driver in this crash. After researching the accident, the FIA changed the rules for the principal roll structures in 2023 and significantly raised their required strength in 2024. The test loads are now applied more horizontally, so that the roll structure is fixed to the monocoque more securely.

Where else is the halo used?

In all FIA single-seater championships, including Formula 2 and Formula 3, the last steps before Formula 1. How the whole ladder of series works is explained in the article on becoming an F1 driver.

The FIA ranks the halo among the biggest safety advances in the 30 years since Imola 1994. Other steps from the same list are collected in the article on Senna’s death.