Traffic circles were popular with European highway designers in the 1930s. The QEW ahad several, until the freeway interchange became standard on the 400 series highways. The QEW / Stoney Creek traffic circle was built in 1938 and wasn't replaced with an interchange until 1978.
The traffic circle bisected the Alexander (later John) Gray farm, where grapes and pears were grown. The family did farm the land around the circle, often getting to the field by going around the circle in their tractor, much to the consteration of motorists.
Credit 1: Michael Gemmell