Well, it’s not where you mix the eggs into the batter. A mixing zone, also called a combined lane, is where bicyclists and motorists can expect to merge. The most common mixings are a right turn lane and bike lane at an intersection. A mixing zone has markings for motorists and bicyclists. Typically, a mixing zone is identified by the dashed lines like in the image below.

A mixing zone benefits motorists and bicyclists. It gives a visual cue to expect each other in the shared lane. One experimental use of a mixing zone is a dashed bicycle lane. Criteria for this use is currently very strict. A mixing zone also guides bicyclists to the left of turning cars.