There is a variety of answers to this question and it comes down to answering the question: What are you going to do with the information?In short it really can be a choice you make, in deciding what information or value you are trying to get out of their data, what logic you employ, and what sort of story you are trying to tell. Some people only include wrench time because they already have to pay them to be at work anyway. The only time where we include travel time is for emergency/overtime work.If you track all time related to the work being done including travel, preparation, cleanup and traffic control because that is the true cost. If you outsource the work the cost from a contractor would include all cost. Often a question asked of government is are they competitive if you do not track all cost you cannot answer the question. If you track only wrench time you do not know the true unit cost. If you are charging others for your work such as another department you are losing money as often more time is spend preparing, travelling, establishing traffic control and job cleanup. Also If you only track time actually doing the work to compute actual cost you would have to add the other non-wrench cost to an overhead rate which would make rate very high.