testing accident at the Mid-Ohio Sports Car Course when his Renault Le Car Turbo struck a sandbank, leaving him dead on arrival with head injuries, IMSA officials decided that some sort of protection was required to help prevent injuries from sudden stops, especially during accidents. A major cause of death among drivers during races was through violent head movements, where the body remains in place because of the seat belts, but the momentum keeps the head moving forward, causing a basilar skull fracture, resulting in serious injury or immediate death. Notable race car drivers who died from basilar skull fractures include: Formula 1 driver Roland Ratzenberger in the 1994 San Marino Formula One Grand Prix. Indy 500 drivers Scott Brayton, Bill Vukovich and Tony Bettenhausen NASCAR drivers Adam Petty, Kenny Irwin Jr., Terry Schoonover, Grant Adcox, Neil Bonnett, John Nemechek, Dale Earnhardt, J. D. McDuffie, and Clifford Allison ARCA driver Blaise Alexander CART driver Gonzalo Rodríguez Trans Am, Sports Car Club of America (SCCA) driver Jim Fitzgerald While death from such injuries is usually immediate, some drivers have survived basilar skull fractures, such as NASCAR's Ernie Irvan and F1's Philippe Streiff. Hubbard had extensive experience as a biomechanical crash engineer, including in General Motors' auto safety program. His first prototype was developed in 1985, and in crash tests in 1989 – the first to use crash sleds and crash dummies using race car seat belt harnesses – the energy exerted on the head and neck was lowered by approximately 80%. Prior tests had established the thresholds for acute basilar skull fracture to be 740 lbs of vertical neck tension and 700 lbs of forward neck shear; the HANS device greatly reduced both these values to 210 lbs. Neck compression was also reduced by about 28 millimetres. After major racing safety companies declined to produce the product, Hubbard and Downing formed Hubbard Downing Inc., to develop, manufacture, sell and promote the HANS in 1990. However, the product languished until 1994, when Formula One showed interest in the wake of the deaths of Roland Ratzenberger and Ayrton Senna. In 1999, CART driver Gonzalo Rodríguez was killed after suffering a basilar skull fracture in a crash. At the same time, Mercedes was completing research of the HANS on behalf of the FIA for Formula One, finally deciding that it out-performed their airbag project. The device was first adopted by the National Hot Rod