Knoxville Raceway is an example of what type of racing that began before World War I?
Knoxville Raceway: Knoxville Raceway is a semi-banked 1/2 mile dirt oval raceway (zook clay) located at the Marion County Fairgrounds in Knoxville, Iowa, United States. Dirt track racing: Dirt track racing is a type of auto racing performed on clay or dirt surfaced oval tracks. Dirt track racing:  It began in the United States before World War I and became widespread during the 1920s and 1930s.
i don't know