MotorTrend profiles the Cozy Coupe’s creator, Jim Mariol:

The most clever part was the overall conception: a pedal-car-like experience without the pedals, called a foot-to-floor toy. Something kids too little for pedal cars could also enjoy without excluding older kids who could also fit inside. Mariol was inspired scooting around on a wheeled office chair, using his feet—something within the power of an average little tyke. The design was more than just cute: The roof made it, indeed, cozy and more like a real car than a typical roofless pedal car. And the larger rear wheels and bulkier rear end meant it would be harder to tip over backwards. Add in the long, swoopy door, which of course opens, and you have a primeval car experience, delivered to Little Tikes for consideration in 1979.

I always figured the design was inspired by the Flintstones.

Little Tikes Cozy Coupe: First “Car” for Many Has Roots In Real Car World