When batman the dark knight filmed in chicago howd they keep the public outa the way, did ppl take off of work?

Simple. They let people get in and out when the set is in down-time. Once, the camera starts rolling, they block the traffic once again until the director cuts and starts setting up for the next shot. So during each take, traffic officers will temporarily reopen streets or let pedestrians walk by. It shouldn't have effected business extensively.