Calvin Lee Niday^[1] (April 29, 1914^[2] – February 14, 1988) was an American racecar driver who was born in Turlock, California and died in Lancaster, California.

He lost his leg in a motorcycle accident after high school, but it did not affect his race car driving career. Cal is also noted as the first racer to wear a modern-style Bell helmet in the Indy 500.^[3] Niday is one of three drivers to have participated in the Indianapolis 500 with a prosthetic leg, along with Al Miller and Bill Schindler.^[4] The Indianapolis 500 was part of the FIA World Championship from 1950 through 1960. Drivers competing at Indy during those years were credited with World Championship points and participation. During his racing career, Niday travelled to Australia to race Midgets (known as Speedcars in Australia). In 1948, Niday won the 3rd running of the Australian Speedcar Grand Prix at the famous Sydney Showground Speedway. Cal Niday participated in three World Championship races but scored no World Championship points. He died from a heart attack after being thrown from a vintage open-wheeler at Willow Springs raceway.