Quarter Midgets are for kids.  

What is Quarter Midget Racing All About?

Racing Quarter midgets is a family-oriented sport that involves racing in specially prepared cars. The cars, rules, and safety procedures are designed specifically for kids. They race on oval tracks approximately 1/20 of a mile. A child who is 5 to 16 years of age can race. Safety features include full roll cages, multi-point seat harnesses, full-face helmets, and other gear. This sport has fewer injuries than little-league football. The racing environment is about children and family. Not only do kids learn valuable skills and sportsmanship, but they also make new friends. Mom and Dad will make new friends too. 

A Quarter Midget car is a scaled-down version of an actual midget racer, approximately 1/4 scale.   The cars are built around a tubular frame and are fully suspended with springs and shocks.  The bodies are fiberglass or sheet metal usually painted to the driver’s preference. Surrounding the driver is a chrome-moly roll cage and nerf bars.  The engines are single cylinder and manufactured by Honda or Briggs & Stratton.  These air-cooled 4-cycle engines are reliable and can produce as much as 10,000 RPMs in their more highly modified forms