American-born English automobile and motorboat racer who set three world land speed records.

Educated at Eton and Sandhurst, Segrave served with the Royal Air Force in World War I. During the war he became interested in automobile racing by a visit to the Sheepshead Bay, Long Island, N.Y., course. He won the French Grand Prix (Grand Prix racing) (1923) and the San Sebastian Grand Prix (1924) in Spain, in which he was the first racer to wear a crash helmet. He also won the 200-mile (322-kilometre) race at Brooklands in England (1921, 1925, and 1926) and competed in many hill climbs and speed trials from 1914 to 1927.

In 1926 he first broke the land speed record, driving a Sunbeam at 152.33 mile/h (miles per hour 【245.15 km/h】). On March 29, 1927, at Daytona, Fla., driving a 1,000-horsepower Sunbeam with a World War I aero-engine, he became the first driver to exceed 200 mile/h (320 km/h) and established a new record of 203.79 mile/h (327.97 km/h). He set a third record of 231.44 mile/h (372.48 km/h) in March 1929.

Segrave began racing motorboats in 1927, winning the International Championship at Miami, Fla., in 1928. Immediately after setting a water speed record of 85.8 knots, he was fatally injured when his boat—traveling at a speed of more than 86 knots—broke apart, presumably after hitting a floating tree limb. His book, The Lure of Speed, was published in 1928. He was knighted in 1929.