exception is itinerant worker

The purpose of allowing deductions for out-of-town business travel expenses is to give you a tax break for all the duplicative expenses incurred while at the temporary work location. However, an itinerant worker (such as a traveling salesman or self-employed casualty insurance adjuster who moves from one disaster site to the next) doesn't have any tax home and therefore does not have any duplicative expenses. As a result, itinerant workers can only deduct transportation costs between work locations (no deductions for lodging, meals, and incidentals).