Innovations in car design began appearing at the track in the late 1930s, with Bugatti and Alfa Romeo running highly aerodynamic bodywork in order to run down the Mulsanne Straight at faster speeds.
A finais de 1930 comezaron a aparecer na pista as primeiras innovacións no deseño dos coches, con Bugatti e Alfa Romeo competindo cunha carrocería altamente aerodinámica co fin de correr pola recta Mulsanne a maiores velocidades.