The halo is a driver crash-protection system used in open-wheel racing series, which consists of a curved bar placed to protect the driver's head.
The first tests of the halo were carried out in 2016 and in July 2017. Since the 2018 season the FIA has made the halo mandatory on every vehicle in Formula 1, Formula 2, Formula 3, Formula E and also Formula 4 (starting by 2021) as a new safety measure. Some other open-wheel racing series also utilise the halo, such as IndyCar Series, Super Formula, and Australian S5000 Championship. The IndyCar halo is used as a structural frame for the aeroscreen.
The system consists of a bar that surrounds the driver's head and is connected by three points to the vehicle frame. The halo is made of titanium and weighed around 7 kilograms (15 lb) in the version presented in 2016, then rose to 9 kilograms (20 lb) in 2017.
The system is not developed by the teams, but is manufactured by three approved external manufacturers chosen by the FIA and has the same specification for all vehicles.
In a simulation performed by the FIA, using the data of 40 real incidents, the use of the system led to a 17% theoretical increase in the survival rate of the driver.
The FIA for development examined three fundamental scenarios--collision between two vehicles, contact between a vehicle and the surrounding environment (such as barriers) and collisions with vehicles and debris. Tests have shown that the halo system can significantly reduce the risk of injury to the driver. Moreover, in many cases the system was able to prevent the helmet from coming into contact with a barrier when checked against a series of accidents that had occurred in the past. During the study of the last case it was found that the halo was able to deflect large objects and provide greater protection against smaller debris.
In August 2017 the Dallara F2 2018, a new Formula 2 car, was presented and was the first to install the halo system. The SRT05e Formula E car presented in January 2018 had a halo. In November 2018, the 2019 FIA Formula 3 car, which was unveiled in Abu Dhabi, installed the halo too.
As an alternative to the halo system, Red Bull Advanced Technologies developed the "aeroscreen". The design, which was similar to a small fairing, did not receive much interest from the FIA. After the drivers had expressed their opposition to the introduction of the halo system, the FIA developed the "shield", a polyvinyl chloride windscreen based on the airbrush concept. In 2019 the aeroscreen was adapted to utilise the halo as a structural frame for use in IndyCar.
Sebastian Vettel was the first and only driver to try the shield in a Formula 1 car. During the free practice for the 2017 British Grand Prix, he completed a lap with the new system before ending the test early. He complained of distorted and blurred vision that prevented him from driving. Its introduction was subsequently excluded, as there was no guarantee that the issues with the shield could be solved in time for the 2018 season.
The system has aroused some criticism, including that of Niki Lauda, who claimed that this system distorts the "essence of racing cars". The system has also proved unpopular with fans, who have said that it is visually unappealing, against the concept of open-cockpit racing, and obstructs the driver's vision. Other former drivers, including Jackie Stewart, welcomed the system and compared it to the introduction of seat belts, which had been similarly criticised, but then became the norm also on road cars.
Despite initial criticism, the halo was praised by the community following two incidents where the halo was struck by another car--one in the Formula Two race at Spain, where Tadasuke Makino's halo was landed on by fellow countryman Nirei Fukuzumi's car, and one in the Belgian Grand Prix, where Charles Leclerc's halo was struck by Fernando Alonso's airborne McLaren, with both of their haloes showing visible damage from the impact. Both Makino and Leclerc credited the halo for possibly saving their lives, and Mercedes team principal Toto Wolff, who had criticised the halo earlier in the season, admitted that it had proved itself following Leclerc's incident.
The halo was credited with saving the life of Alex Peroni after his vehicle became airborne and crashed during a Formula 3 event at Monza on 7 September 2019. It also played a role in protecting Romain Grosjean at the 2020 Bahrain Grand Prix where, after hitting Daniil Kvyat's car, he crashed into the barriers head-on. The car split the crash barrier, allowing the car to slip through in between and splitting off the back of the car from the safety cell. The halo hit the upper section of the barrier, protecting Grosjean's head from the impact. In a similar accident at the 1974 United States Grand Prix, driver Helmuth Koinigg was decapitated. Despite initial concern over drivers ability to evacuate quickly being impaired by the halo, Grosjean was able to climb out almost immediately, which was critical as the car started burning instantly. He emerged from the flames, with burns on his hands and ankles, and non-life threatening injuries. "I wasn't for the halo some years ago, but I think it's the greatest thing that we've brought to Formula 1, and without it I wouldn't be able to speak with you today," Grosjean said from his hospital bed afterward.