From a service provider’s perspective, a professional who is on travel isn’t fully available for other work. So (says the provider), the customer should pay for that opportunity cost.
From the customer’s perspective, the opportunity cost a professional incurs in traveling on business is something the provider should absorb in its internal cost structure. This is especially true (says the customer) if the traveler might be doing work for other customers during the travel.
A possible compromise might be for the customer to pay for travel time at a reduced rate.
Follow me
Signing a business contract:
there’s also a difference between traveling during business hours and off hours. law firms, for example, typically charge full freight for the former and not at all or a reduced rate for the latter (again, as a function of opportunity costs). in any event, there should be no charge if the provider can (but chooses not to) or actually does do work billable to another client during travel.
@randomjohn writes: in any event, there should be no charge if the provider can (but chooses not to) or actually does do work billable to another client during travel.
The prohibition against double-billing is pretty common, but I’m not sure how a client could (or would want to) police the bold-faced part.
My company provides flexible time billing software for professionals, and some of our customers charge travel time and others don’t. BUT there are others who use the time tracking timer on their phones/laptops to charge billable time while they are commuting. It’s a best of both worlds: the customer only is charged while the professional is working and the professional can accurately track billable time while they are commuting.