The cost of travel includes all the costs you pay for travel in relation to people. But, as with all the items in item 1 of the schedule of cost components, you are only paid for the costs you actually pay. So, if you pay your operatives for travel time, which presumably will not often be the case, you are entitled to recover that cost either under item 13(a) or under item 12(d). If you do not pay them, there is no defined cost that arises. The same applies if you pay people a travel allowance instead.