I live 35 minutes and work two EL stops from ORD. My drive radius is roughly 5-6 hours, but it depends on the destination. There are several non-hub or small-hub cities near ORD that you'd think would be a snap to fly to, but are the first ones to get hit with cancellations if the weather gets bad. Specifically STL, IND, and CVG in my experience. If it weren't for that, my drive radius would be a lot less.