Drivers who skirted the track edge would send rocks flying in the middle of the road and into the path of pursuing competitors. In the most serious incident at the 1972 French Grand Prix, a stone thrown from Emerson Fittipaldi's Lotus penetrated the helmet visor of Helmut Marko, blinding him in the left eye and ending his racing career.
Emerson Fittipaldi
Helmut Marko