Your kid can dart into the street even when you're with them. You should teach your kids about traffic safety at an early age, and ideally have made this particular trip with them several times before so that they (1) know how to behave and (2) don't get lost and (3) have been introduced to the shopkeep and others in the neighborhood.

It's pretty easy to gradually ramp up to this and to continue ramping up to more indepdendence at a much faster pace than most parents do.