Following a series of serious incidents in open-wheel racing – including the fatal accidents of Henry Surtees and Justin Wilson – in which drivers were struck in the head by tyres or debris, the FIA announced plans to introduce additional mandatory cockpit protection with 2018 given as the first year for its introduction. Several solutions were tested, with the final design subject to feedback from teams and drivers. Each design was created to deflect debris away from a driver's head without compromising their visibility or the ability of safety marshals to access the cockpit and extract a driver and their seat in the event of a serious accident or medical emergency, with a series of serious accidents – such as the fatal accidents of Jules Bianchi and Dan Wheldon – recreated to simulate the ability of devices to withstand a serious impact. The FIA ultimately settled on the "halo", a wishbone-shaped frame mounted above and around the driver's head and anchored to the monocoque forward of the cockpit. Seventeen accidents were examined as case studies, with the FIA concluding that the halo would have prevented injuries in fifteen of them. In the other two instances – most notably Jules Bianchi's fatal accident – the FIA concluded that although the halo would not have prevented driver injuries, it would not have contributed to or complicated the outcome of the accidents. Once introduced, the halo concept is scheduled to be applied to other FIA-sanctioned open-wheel racing categories including Formula 2, Formula 3 and Formula E, with 2020 earmarked as the deadline for all FIA-sanctioned open-wheel racing series to adopt the halo.