Hawthorn was killed in his Jag on the 'Hogs Back', the A3 near Guildford, Surrey. His mate was racing a Merc & Hawthorn lost it playing catch up. And I don't think there wasn't a bypass in those days either.
PS Quote from Wiki: The crash has been ascribed to combination of high speed, bad weather, competitiveness and impulsiveness. Rob Walker's 300 SL Mercedes was ahead of him. Perhaps Hawthorn pushed his car to pass Walker's. Hawthorn's Jaguar, nicknamed "the Merceater" was heavily modified for high power and speed. "No Kraut car could overtake or outaccelerate" Hawthorn's Jaguar (these are the words in his biography Challenge Me The Race) - a close relation had been killed in the war, hence his dislike of Germans.